NumPy数组（1、数组初探）

灰太狼 2022-07-24 04:14 202阅读 0赞

#     #

目前我的工作是将NumPy引入到Pyston中（一款Dropbox实现的[Python][]编译器/解释器）。在工作过程中，我深入接触了NumPy源码，了解其实现并提交了PR修复NumPy的bug。在与NumPy源码以及NumPy开发者打交道的过程中，我发现当今中文NumPy教程大部分都是翻译或参考英文文档，因此导致了许多疏漏。比如NumPy数组中的broadcast功能，几乎所有中文文档都翻译为“广播”。而NumPy的开发者之一，回复到“broadcast is a compound -- native English speakers can see that it's " broad" + "cast" = "cast (scatter, distribute) broadly, I guess "cast (scatter, distribute) broadly" probably is closer to the meaning（NumPy中的含义）"。有鉴于此，我打算启动一个项目，以我对NumPy使用以及源码层面的了解编写一个系列的教程。

地址随后会更新。CSDN的排版（列表）怎么显示不正常了。。。

##  ##

## NumPy数组 ##

NumPy数组是一个多维数组对象，称为ndarray。其由两部分组成：

*  实际的数据
 *  描述这些数据的元数据

大部分操作仅针对于元数据，而不改变底层实际的数据。

关于NumPy数组有几点必需了解的：

*  NumPy数组的下标从0开始。
 *  同一个NumPy数组中所有元素的类型必须是相同的。

## NumPy数组属性 ##

在详细介绍NumPy数组之前。先详细介绍下NumPy数组的基本属性。NumPy数组的维数称为秩（rank），一维数组的秩为1，二维数组的秩为2，以此类推。在NumPy中，每一个线性的数组称为是一个轴（axes），秩其实是描述轴的数量。比如说，二维数组相当于是两个一维数组，其中第一个一维数组中每个元素又是一个一维数组。所以一维数组就是NumPy中的轴（axes），第一个轴相当于是底层数组，第二个轴是底层数组里的数组。而轴的数量——秩，就是数组的维数。

NumPy的数组中比较重要ndarray对象属性有：

*  ndarray.ndim：数组的维数（即数组轴的个数），等于秩。最常见的为二维数组（矩阵）。
 *  ndarray.shape：数组的维度。为一个表示数组在每个维度上大小的整数元组。例如二维数组中，表示数组的“行数”和“列数”。ndarray.shape返回一个元组，这个元组的长度就是维度的数目，即ndim属性。
 *  ndarray.size：数组元素的总个数，等于shape属性中元组元素的乘积。
 *  ndarray.dtype：表示数组中元素类型的对象，可使用标准的Python类型创建或指定dtype。另外也可使用前一篇文章中介绍的NumPy提供的数据类型。
 *  ndarray.itemsize：数组中每个元素的字节大小。例如，一个元素类型为float64的数组itemsiz属性值为8(float64占用64个bits，每个字节长度为8，所以64/8，占用8个字节），又如，一个元素类型为complex32的数组item属性为4（32/8）。
 *  ndarray.data：包含实际数组元素的缓冲区，由于一般通过数组的索引获取元素，所以通常不需要使用这个属性。

## 创建数组    ##

<span style="font-size: 18px;">　　<span style="font-family: SimSun; font-size: 14px;"><span lang="zh-CN">先来介绍</span>创建数组。<span lang="zh-CN">创建数组的方法有很多。</span>如可以使用<span lang="en-US">array</span>函数从常规的<span lang="en-US">Python</span>列表和元组创造数组。所创建的数组类型由原序列中的元素类型推导而来。</span><span style="font-family: SimSun;">　　　</span></span><div class="dp-highlighter bg_python" style="font-family: Consolas, 'Courier New', Courier, mono, serif; font-size: 12px; width: 700.912px; overflow: auto; padding-top: 1px; margin: 18px 0px !important; background-color: rgb(231, 229, 220);"><div class="bar" style="padding-left: 45px;"><div class="tools" style="padding: 3px 8px 10px 10px; font-stretch: normal; font-size: 9px; line-height: normal; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; color: silver; border-left-width: 3px; border-left-style: solid; border-left-color: rgb(108, 226, 108); background-color: rgb(248, 248, 248);"><strong>[python]</strong> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="ViewSource" title="view plain" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_plain.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">view plain</a><span data-mod="popu_168"> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="CopyToClipboard" title="copy" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_copy.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">copy</a></span><div style="position: absolute; left: 653px; top: 1912px; width: 18px; height: 18px; z-index: 99;"></div><span data-mod="popu_169"> </span></div></div><ol start="1" class="dp-py" style="padding: 0px; border: none; color: rgb(92, 92, 92); margin: 0px 0px 1px 45px !important; background-color: rgb(255, 255, 255);"><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;"><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">>>> </span><span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">from</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> numpy </span><span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">import</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> *  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　  </span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> a = array( [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">,</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">,</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">] )　　　  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> a  </span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    array([<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">, </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">, </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">])  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> a.dtype  </span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    dtype(<span class="string" style="margin: 0px; padding: 0px; border: none; color: blue; background-color: inherit;">'int32'</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> b = array([<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">1.2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">, </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3.5</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">, </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">5.1</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">])　　　  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> b.dtype  </span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    dtype(<span class="string" style="margin: 0px; padding: 0px; border: none; color: blue; background-color: inherit;">'float64'</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)  </span></span></li></ol></div>

使用array函数创建时，参数必须是由方括号括起来的列表，而不能使用多个数值作为参数调用array。

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> a = array(1,2,3,4)    \# 错误  
2.  >>> a = array(\[1,2,3,4\])  \# 正确

可使用双重序列来表示二维的数组，三重序列表示三维数组，以此类推。

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> b = array( \[ (1.5,2,3), (4,5,6) \] )　　  
2.  >>> b  
3.      array(\[\[ 1.5,  2. ,  3. \],  
4.  　　　     \[ 4. ,  5. ,  6. \]\])

可以在创建时显式指定数组中元素的类型

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> c = array( \[ \[1,2\], \[3,4\] \], dtype=complex)  
2.  >>> c  
3.      array(\[\[ 1.\+0.j,  2.\+0.j\],  
4.  　　　    \[ 3.\+0.j,  4.\+0.j\]\])

通常，刚开始时数组的元素未知，而数组的大小已知。因此，NumPy提供了一些使用占位符创建数组的函数。这些函数有助于满足除了数组扩展的需要，同时降低了高昂的运算开销。

用函数zeros可创建一个全是0的数组，用函数ones可创建一个全为1的数组，函数empty创建一个内容随机并且依赖与内存状态的数组。默认创建的数组类型(dtype)都是float64。

可以哟娜特d.dtype.itemsize来查看数组中元素占用的字节数目。

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> d = zeros((3,4))  
2.  >>> d.dtype  
3.  dtype('float64')  
4.  >>> d  
5.  array(\[\[ 0.,  0.,  0.,  0.\],  
6.  　　   \[ 0.,  0.,  0.,  0.\],  
7.  　　   \[ 0.,  0.,  0.,  0.\]\])  
8.  >>> d.dtype.itemsize  
9.  8

也可以自己制定数组中元素的类型

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> ones( (2,3,4), dtype=int16 )  \#手动指定数组中元素类型  
2.        array(\[\[\[1, 1, 1, 1\],  
3.  　　　        \[1, 1, 1, 1\],  
4.  　　　        \[1, 1, 1, 1\]\],  
5.  　　　  
6.  　　　       \[\[1, 1, 1, 1\],  
7.  　　　        \[1, 1, 1, 1\],  
8.  　　　        \[1, 1, 1, 1\]\]\], dtype=int16)  
9.  >>> empty((2,3))  
10. 　　　array(\[\[  2.65565858e\-316,   0.00000000e\+000,   0.00000000e\+000\],  
11. 　　　       \[  0.00000000e\+000,   0.00000000e\+000,   0.00000000e\+000\]\])

NumPy提供一个类似arange的函数返回一个数列形式的数组:

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> arange(10, 30, 5)  
2.      array(\[10, 15, 20, 25\])

以10开始，差值为5的等差数列。该函数不仅接受整数，还接受浮点参数：

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> arange(0,2,0.5)  
2.      array(\[ 0. ,  0.5,  1. ,  1.5\])

当arange使用浮点数参数时，由于浮点数精度有限，通常无法预测获得的元素个数。因此，最好使用函数linspace去接收我们想要的元素个数来代替用range来指定步长。linespace用法如下，将在通用函数一节中详细介绍。

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> numpy.linspace(-1, 0, 5)  
2.          array(\[-1.  , -0.75, -0.5 , -0.25,  0.  \])

数组中的元素是通过下标来访问的，可以通过方括号括起一个下标来访问数组中单一一个元素，也可以以切片的形式访问数组中多个元素。关于切片访问，将在切片一节介绍。

**知识点：****NumPy****中的数据类型**  
对于科学计算来说，Python中自带的整型、浮点型和复数类型远远不够，因此NumPy中添加了许多数据类型。如下：

<table style="color:rgb(51,51,51); font-family:Arial; font-size:14px; line-height:26px">  
 <span style="font-size:18px">NumPy中的基本数据类型</span>  
 <tbody> 
  <tr> 
   <td align="center">名称</td> 
   <td align="center">描述</td> 
  </tr> 
  <tr> 
   <td>bool</td> 
   <td>用一个字节存储的布尔类型（True或False）</td> 
  </tr> 
  <tr> 
   <td>inti</td> 
   <td>由所在平台决定其大小的整数（一般为int32或int64）</td> 
  </tr> 
  <tr> 
   <td>int8</td> 
   <td>一个字节大小，-128 至 127</td> 
  </tr> 
  <tr> 
   <td>int16</td> 
   <td>整数，-32768 至 32767</td> 
  </tr> 
  <tr> 
   <td>int32</td> 
   <td>整数，-2 ** 31 至 2 ** 32 -1</td> 
  </tr> 
  <tr> 
   <td>int64</td> 
   <td>整数，-2 ** 63 至 2 ** 63 - 1</td> 
  </tr> 
  <tr> 
   <td>uint8</td> 
   <td>无符号整数，0 至 255</td> 
  </tr> 
  <tr> 
   <td>uint16</td> 
   <td>无符号整数，0 至 65535</td> 
  </tr> 
  <tr> 
   <td>uint32</td> 
   <td>无符号整数，0 至 2 ** 32 - 1</td> 
  </tr> 
  <tr> 
   <td>uint64</td> 
   <td>无符号整数，0 至 2 ** 64 - 1</td> 
  </tr> 
  <tr> 
   <td>float16</td> 
   <td>半精度浮点数：16位，正负号1位，指数5位，精度10位</td> 
  </tr> 
  <tr> 
   <td>float32</td> 
   <td>单精度浮点数：32位，正负号1位，指数8位，精度23位</td> 
  </tr> 
  <tr> 
   <td>float64或float</td> 
   <td>双精度浮点数：64位，正负号1位，指数11位，精度52位</td> 
  </tr> 
  <tr> 
   <td>complex64</td> 
   <td>复数，分别用两个32位浮点数表示实部和虚部</td> 
  </tr> 
  <tr> 
   <td>complex128或complex</td> 
   <td>复数，分别用两个64位浮点数表示实部和虚部</td> 
  </tr> 
 </tbody> 
</table>

NumPy类型转换方式如下：

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> float64(42)  
2.      42.0  
3.  >>> int8(42.0)  
4.      42  
5.  >>> bool(42)  
6.      True  
7.  >>> bool(42.0)  
8.      True  
9.  >>> float(True)  
10.     1.0

许多函数的参数中可以指定参数的类型，当然，这个类型参数是可选的。如下：

**\[python\]**  [view plain][]   [copy][view plain]

1.  >>> arange(7, dtype=uint16)  
2.      array(\[0, 1, 2, 3, 4, 5, 6\], dtype=uint16)

## 输出数组 ##

<span style="font-size: 18px;">    <span style="font-size: 14px;">当输出一个数组时，<span style="font-family: 'Courier New', monospace;"><span lang="en-US">NumPy</span></span>以特定的布局用类似嵌套列表的形式显示：
    </span></span>

*  第一行从左到右输出
 *  每行依次自上而下输出
 *  每个切片通过一个空行与下一个隔开
 *  一维数组被打印成行，二维数组成矩阵，三维数组成矩阵列表。

<span style="font-size: 18px;"> 　　　
    </span><div class="dp-highlighter bg_python" style="font-family: Consolas, 'Courier New', Courier, mono, serif; font-size: 12px; width: 700.912px; overflow: auto; padding-top: 1px; margin: 18px 0px !important; background-color: rgb(231, 229, 220);"><div class="bar" style="padding-left: 45px;"><div class="tools" style="padding: 3px 8px 10px 10px; font-stretch: normal; font-size: 9px; line-height: normal; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; color: silver; border-left-width: 3px; border-left-style: solid; border-left-color: rgb(108, 226, 108); background-color: rgb(248, 248, 248);"><strong>[python]</strong> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="ViewSource" title="view plain" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_plain.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">view plain</a><span data-mod="popu_168"> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="CopyToClipboard" title="copy" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_copy.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">copy</a></span><div style="position: absolute; left: 653px; top: 5163px; width: 18px; height: 18px; z-index: 99;"></div><span data-mod="popu_169"> </span></div></div><ol start="1" class="dp-py" style="padding: 0px; border: none; color: rgb(92, 92, 92); margin: 0px 0px 1px 45px !important; background-color: rgb(255, 255, 255);"><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;"><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">>>> a = arange(</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">6</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)                         </span><span class="comment" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 130, 0); background-color: inherit;"># 1d array</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> <span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">print</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> a  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">0</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">1</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">5</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　  </span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> b = arange(<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">12</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">).reshape(</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">,</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)           </span><span class="comment" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 130, 0); background-color: inherit;"># 2d array</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> <span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">print</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> b  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [[ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">0</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">1</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">5</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">6</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">7</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">8</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">10</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">11</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]]　　　  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> c = arange(<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">24</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">).reshape(</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">,</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">,</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)         </span><span class="comment" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 130, 0); background-color: inherit;"># 3d array</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> <span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">print</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> c  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [[[ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">0</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">1</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">3</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">4</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">5</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">6</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">7</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">8</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">10</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">11</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　  </span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [[<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">12</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">13</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">14</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">15</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">16</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">17</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">18</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">19</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">    [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">20</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">21</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">22</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">23</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]]]  </span></span></li></ol></div><span style="font-size: 18px;"><span style="font-size: 14px;"><span style="font-family: SimSun;">    <span lang="en-US">reshape</span>将在下一篇文章中介绍　
        如果一个数组太长，则<span lang="en-US">NumPy</span>自动省略中间部分而只打印两端的数据：　　</span>　</span></span><div class="dp-highlighter bg_python" style="font-family: Consolas, 'Courier New', Courier, mono, serif; font-size: 12px; width: 700.912px; overflow: auto; padding-top: 1px; margin: 18px 0px !important; background-color: rgb(231, 229, 220);"><div class="bar" style="padding-left: 45px;"><div class="tools" style="padding: 3px 8px 10px 10px; font-stretch: normal; font-size: 9px; line-height: normal; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; color: silver; border-left-width: 3px; border-left-style: solid; border-left-color: rgb(108, 226, 108); background-color: rgb(248, 248, 248);"><strong>[python]</strong> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="ViewSource" title="view plain" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_plain.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">view plain</a><span data-mod="popu_168"> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="CopyToClipboard" title="copy" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_copy.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">copy</a></span><div style="position: absolute; left: 653px; top: 5618px; width: 18px; height: 18px; z-index: 99;"></div><span data-mod="popu_169"> </span></div></div><ol start="1" class="dp-py" style="padding: 0px; border: none; color: rgb(92, 92, 92); margin: 0px 0px 1px 45px !important; background-color: rgb(255, 255, 255);"><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;"><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">>>> </span><span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">print</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> arange(</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">10000</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　[   <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">0</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">    </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">1</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">    </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ..., </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9997</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9998</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9999</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　  </span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">>>> <span class="keyword" style="margin: 0px; padding: 0px; border: none; color: rgb(0, 102, 153); font-weight: bold; background-color: inherit;">print</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> arange(</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">10000</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">).reshape(</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">100</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">,</span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">100</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　[[   <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">0</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">    </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">1</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">    </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">2</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ...,   </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">97</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">   </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">98</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">   </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">99</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　 [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">100</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">101</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">102</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ...,  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">197</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">198</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">199</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　 [ <span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">200</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">201</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">202</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ...,  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">297</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">298</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">  </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">299</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　 ...,  </span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　 [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9700</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9701</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9702</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ..., </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9797</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9798</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9799</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important; background-color: rgb(248, 248, 248);"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　 [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9800</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9801</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9802</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ..., </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9897</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9898</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9899</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]  </span></span></li><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;">　　　 [<span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9900</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9901</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9902</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> ..., </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9997</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9998</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;"> </span><span class="number" style="margin: 0px; padding: 0px; border: none; background-color: inherit;">9999</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">]]  </span></span></li></ol></div><span style="font-size: 18px;">
    <span style="font-size: 14px;">　　可通过</span></span><span style="font-size: 18px;"><span style="font-size: 14px;">设置<span style="font-family: 'Courier New', monospace;"><span lang="en-US">printoptions</span></span>参数来</span></span><span style="font-size: 18px;"><span style="font-size: 14px;">禁用<span style="font-family: 'Courier New', monospace;"><span lang="en-US">NumPy</span></span>的这种行为并强制打印整个数组。</span>
    </span><pre class="cjk" name="code" style="white-space: pre-wrap; word-wrap: break-word;"><div class="dp-highlighter bg_python" style="font-family: Consolas, 'Courier New', Courier, mono, serif; font-size: 12px; width: 700.912px; overflow: auto; padding-top: 1px; margin: 18px 0px !important; background-color: rgb(231, 229, 220);"><div class="bar" style="padding-left: 45px;"><div class="tools" style="padding: 3px 8px 10px 10px; font-stretch: normal; font-size: 9px; line-height: normal; font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; color: silver; border-left-width: 3px; border-left-style: solid; border-left-color: rgb(108, 226, 108); background-color: rgb(248, 248, 248);"><strong>[python]</strong> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="ViewSource" title="view plain" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_plain.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">view plain</a><span data-mod="popu_168"> <a target=_blank href="http://blog.csdn.net/sunny2038/article/details/9002531#" class="CopyToClipboard" title="copy" style="color: rgb(160, 160, 160); text-decoration: none; border: none; padding: 1px; margin: 0px 10px 0px 0px; font-size: 9px; display: inline-block; width: 16px; height: 16px; text-indent: -2000px; background-image: url("images/default/ico_copy.gif"); background-attachment: initial; background-color: inherit; background-size: initial; background-origin: initial; background-clip: initial; background-position: 0% 0%; background-repeat: no-repeat;">copy</a></span><div style="position: absolute; left: 653px; top: 5933px; width: 18px; height: 18px; z-index: 99;"></div><span data-mod="popu_169"> </span></div></div><ol start="1" class="dp-py" style="padding: 0px; border: none; color: rgb(92, 92, 92); margin: 0px 0px 1px 45px !important; background-color: rgb(255, 255, 255);"><li class="alt" style="border-left-width: 3px; border-style: none none none solid; border-left-color: rgb(108, 226, 108); list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;"><span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;"><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">set_printoptions(threshold=</span><span class="string" style="margin: 0px; padding: 0px; border: none; color: blue; background-color: inherit;">'nan'</span><span style="margin: 0px; padding: 0px; border: none; background-color: inherit;">)  </span></span></li></ol></div><span style="font-size: 18px;"><span id="_xhe_cursor"></span><span style="font-family: 'Courier New', monospace;"><span lang="en-US"></span></span></span>

这样，输出时数组的所有元素都会显示出来。

未完待续，如有错误，敬请指正！

参考文献：

《NumPy for Beginner》  
《Python科学计算》  
《Tentative NumPy Tutorial》

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