第五次课课上代码

曾经终败给现在 2022-05-16 10:13 153阅读 0赞

# 第五次 #

**双重循环——排序（复习）**

**While循环**

### **Break continue** ###

### **字符串（len，取值改值，格式化）** ###

**列表生成式**

>>> for i in range(4):  
for j in range(4):  
print(i,j)

0 0  
0 1  
0 2  
0 3  
1 0  
1 1  
1 2  
1 3  
2 0  
2 1  
2 2  
2 3  
3 0  
3 1  
3 2  
3 3  
>>> for i in range(2):  
for j in range(2):  
for k in range(2):  
print(i,j)

0 0  
0 0  
0 1  
0 1  
1 0  
1 0  
1 1  
1 1  
>>> for i in range(2):  
for j in range(2):  
for k in range(2):  
print(i,j,k)

0 0 0  
0 0 1  
0 1 0  
0 1 1  
1 0 0  
1 0 1  
1 1 0  
1 1 1  
>>> for i in range(2):  
for j in range(2):  
for k in range(2):  
print(j,k)

0 0  
0 1  
1 0  
1 1  
0 0  
0 1  
1 0  
1 1  
>>> l=\[4,5,7,8,2,2\]  
>>> for i in range(1,len(l)):\#意义是第i个元素开始插入i之前的序列（已经有序）  
for j in range(i,0,-1):\#只要比它之前的元素小就交换  
if l\[j\]<l\[j-1\]:  
l\[j\],l\[j-1\]=l\[j-1\],l\[j\]  
else:  
break\#直到比前一个元素大  
  
SyntaxError: inconsistent use of tabs and spaces in indentation  
>>> l=\[1,3,5,7,9\]  
>>> x=4  
>>> l=\[3,7,5,6,4\]  
>>> while x>8:  
print(x)

>>> while x<8:  
print(x)  
x=x+1

4  
5  
6  
7  
>>> while 0:  
print(1)

>>> while x<8:  
print(1)  
if x>10:  
break  
x=x+1

>>> while 1:  
print(1)  
if x>10:  
break  
x=x+1

1  
1  
1  
1  
>>> l=\[3,7,5,6,4\]  
>>> for i in range(1,len(l)):\#意义是第i个元素开始插入i之前的序列（已经有序）  
for j in range(i,0,-1):\#只要比它之前的元素小就交换  
if l\[j\]<l\[j-1\]:  
l\[j\],l\[j-1\]=l\[j-1\],l\[j\]  
else:  
continue\#直到比前一个元素大  
  
SyntaxError: inconsistent use of tabs and spaces in indentation  
>>> for i in range(1,len(l)):\#意义是第i个元素开始插入i之前的序列（已经有序）  
for j in range(i,0,-1):\#只要比它之前的元素小就交换  
if l\[j\]<l\[j-1\]:  
l\[j\],l\[j-1\]=l\[j-1\],l\[j\]  
else:  
continue  
  
SyntaxError: inconsistent use of tabs and spaces in indentation  
>>> for i in range(5):  
if i%2==0:  
continue  
print(i)

1  
3  
>>> for i in range(100):  
if i%2==0:  
continue  
print(i,end=" ")

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99  
>>> l='0123456'  
>>> len(l)  
7  
>>> l\[0\]  
'0'  
>>> l\[0\]=1  
Traceback (most recent call last):  
File "<pyshell\#48>", line 1, in <module>  
l\[0\]=1  
TypeError: 'str' object does not support item assignment  
>>> l=l\[:2\]+'9'+l\[3:\]  
>>> print(l)  
0193456  
>>> 'Hi, %s, you have $%d.' % ('Michael', 1000000)  
'Hi, Michael, you have $1000000.'  
>>> 'Hi, %s, you have $%5d.' % ('Michael', 5)  
'Hi, Michael, you have $ 5.'  
>>> 1\*1=1  
SyntaxError: can't assign to operator  
>>> 9\*9=81  
SyntaxError: can't assign to operator  
>>> 9\*2=18  
SyntaxError: can't assign to operator  
9\*2=18  
>>> l=\[0,1,2,3\]  
>>> l=\[i for i in range(5)\]  
>>> print(i)  
99  
>>> print(l)  
\[0, 1, 2, 3, 4\]  
>>> l=\[0\]\*10  
>>> print(l)  
\[0, 0, 0, 0, 0, 0, 0, 0, 0, 0\]  
>>> l=\[0 for i in range(5)\]  
>>> print(l)  
\[0, 0, 0, 0, 0\]  
>>> l\[0,1,2,3,4\]  
Traceback (most recent call last):  
File "<pyshell\#64>", line 1, in <module>  
l\[0,1,2,3,4\]  
TypeError: list indices must be integers or slices, not tuple  
>>> l=\[0,1,2,3,4\]  
>>> l=\[\[0\],\[1\],\[2\]\]  
>>> l=\[\[0,1\],\[1,2\],\[2,3\]\]  
>>> l\[0\]\[0\]  
0  
>>> l\[1\]\[0\]  
1  
>>> i=0  
>>> print(i)  
0  
>>> l=\[\[0,1\],\[1,2\],\[2,3\]\]  
>>> for i in l:  
print(i)

\[0, 1\]  
\[1, 2\]  
\[2, 3\]  
>>> print("liurujia")  
liurujia  
>>>