What to use to test variable type in python

Testing variable types in Python can be done using the isinstance() function or type() function.

isinstance() function:

isinstance() function to determine whether an object is a known type, similar to type().

Syntax of isinstance() function:

isinstance(object, classinfo)

Parameters:

object -- instance object.

classinfo -- Can be a direct or indirect class name, a basic type, or a tuple consisting of them.

Return value: If the type of the object is the same as the type of parameter two (classinfo), it returns True, otherwise it returns False.

Example:

>>>a = 2
>>> isinstance (a,int)
True
>>> isinstance (a,str)
False
>>> isinstance (a,(str,int,list))    # 是元组中的一个返回 True
True

type() function:

type() function If you only have the first parameter, it returns the type of the object, and the three parameters return New type object.

The following is the syntax of the type() function:

type(object)
type(name, bases, dict)

Parameters:

name -- the name of the class.

bases -- Tuple of base classes.

dict -- Dictionary, namespace variable defined within the class.

Return value:

One parameter returns the object type, three parameters returns the new type object.

The following shows an example of using the type function:

# 一个参数实例
>>> type(1)
<type &#39;int&#39;>
>>> type(&#39;runoob&#39;)
<type &#39;str&#39;>
>>> type([2])
<type &#39;list&#39;>
>>> type({0:&#39;zero&#39;})
<type &#39;dict&#39;>
>>> x = 1  
>>> type( x ) == int    # 判断类型是否相等
True
# 三个参数
>>> class X(object):
...     a = 1
...
>>> X = type(&#39;X&#39;, (object,), dict(a=1))  # 产生一个新的类型 X
>>> X
<class &#39;__main__.X&#39;>

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