python中判断变量的类型

ゝ一纸荒年。 2022-04-11 07:57 198阅读 0赞

原文:[https://www.cnblogs.com/xmnote/p/9334743.html][https_www.cnblogs.com_xmnote_p_9334743.html]

python的数据类型有：数字(int)、浮点(float)、字符串(str)，列表(list)、元组(tuple)、字典(dict)、集合(set)

一般通过以下方法进行判断：

1、isinstance(参数1,参数2)

描述：该函数用来判断一个变量（参数1）是否是已知的变量类型(参数2) 类似于type()

参数1：变量

参数2：可以是直接或间接类名、基本类型或者由它们组成的元组。

返回值: 如果对象的类型与参数二的类型（classinfo）相同则返回 True，否则返回 False

例子:

![复制代码][copycode.gif]

1 #判断变量类型的函数
     2 def typeof(variate):
     3     type=None
     4     if isinstance(variate,int):
     5         type = "int"
     6     elif isinstance(variate,str):
     7         type = "str"
     8     elif isinstance(variate,float):
     9         type = "float"
    10     elif isinstance(variate,list):
    11         type = "list"
    12     elif isinstance(variate,tuple):
    13         type = "tuple"
    14     elif isinstance(variate,dict):
    15         type = "dict"
    16     elif isinstance(variate,set):
    17         type = "set"
    18     return type
    19 # 返回变量类型
    20 def getType(variate):
    21     arr = {"int":"整数","float":"浮点","str":"字符串","list":"列表","tuple":"元组","dict":"字典","set":"集合"}
    22     vartype = typeof(variate)
    23     if not (vartype in arr):
    24         return "未知类型"
    25     return arr[vartype]
    26     
    27 #判断变量是否为整数
    28 money=120
    29 print("{0}是{1}".format(money,getType(money)))
    30 #判断变量是否为字符串
    31 money="120"
    32 print("{0}是{1}".format(money,getType(money)))
    33 money=12.3
    34 print("{0}是{1}".format(money,getType(money)))
    35 #判断变量是否为列表
    36 students=['studentA']
    37 print("{0}是{1}".format(students,getType(students)))
    38 #判断变量是否为元组
    39 students=('studentA','studentB')
    40 print("{0}是{1}".format(students,getType(students)))
    41 #判断变量是否为字典
    42 dictory={"key1":"value1","key2":"value2"}
    43 print("{0}是{1}".format(dictory,getType(dictory)))
    44 #判断变量是否为集合
    45 apple={"apple1","apple2"}
    46 print("{0}是{1}".format(apple,getType(apple)))

![复制代码][copycode.gif]

![1118859-20180719111155592-1613687455.png][]

2、通过与已知类型的常量进行比较

例子：

![复制代码][copycode.gif]

1 #判断变量类型的函数
     2 def typeof(variate):
     3     type1 = ""
     4     if type(variate) == type(1):
     5         type1 = "int"
     6     elif type(variate) == type("str"):
     7         type1 = "str"
     8     elif type(variate) == type(12.3):
     9         type1 = "float"
    10     elif type(variate) == type([1]):
    11         type1 = "list"
    12     elif type(variate) == type(()):
    13         type1 = "tuple"
    14     elif type(variate) == type({"key1":"123"}):
    15         type1 = "dict"
    16     elif type(variate) == type({"key1"}):
    17         type1 = "set"
    18     return type1
    19 # 返回变量类型
    20 def getType(variate):
    21     arr = {"int":"整数","float":"浮点","str":"字符串","list":"列表","tuple":"元组","dict":"字典","set":"集合"}
    22     vartype = typeof(variate)
    23     if not (vartype in arr):
    24         return "未知类型"
    25     return arr[vartype]
    26     
    27 #判断变量是否为整数
    28 money=120
    29 print("{0}是{1}".format(money,getType(money)))
    30 #判断变量是否为字符串
    31 money="120"
    32 print("{0}是{1}".format(money,getType(money)))
    33 money=12.3
    34 print("{0}是{1}".format(money,getType(money)))
    35 #判断变量是否为列表
    36 students=['studentA']
    37 print("{0}是{1}".format(students,getType(students)))
    38 #判断变量是否为元组
    39 students=('studentA','studentB')
    40 print("{0}是{1}".format(students,getType(students)))
    41 #判断变量是否为字典
    42 dictory={"key1":"value1","key2":"value2"}
    43 print("{0}是{1}".format(dictory,getType(dictory)))
    44 #判断变量是否为集合
    45 apple={"apple1","apple2"}
    46 print("{0}是{1}".format(apple,getType(apple)))

![复制代码][copycode.gif]

![1118859-20180719111155592-1613687455.png][]

** 补充:**

isinstance() 与 type() 区别：

*   *  type() 不会认为子类是一种父类类型，不考虑继承关系。
     *  isinstance() 会认为子类是一种父类类型，考虑继承关系。

如果要判断两个类型是否相同推荐使用 isinstance()。

[https_www.cnblogs.com_xmnote_p_9334743.html]: https://www.cnblogs.com/xmnote/p/9334743.html
[copycode.gif]: /images/20220411/2bb6990809c24ecf8f29dde47227bd85.png
[1118859-20180719111155592-1613687455.png]: /images/20220411/9e271037de09479d963c2c9a0ecc252c.png