Typeerror: 'STR' object is not callable error reason

I encountered a problem writing code today TypeError: 'str' object is not callable.

The reason for the error 1

Let me show you my code ：（ Code function description ： Match numbers with regular expressions and +1 operation , Then replace the original number ）

str='literal books=1000'
def add1(match):
    val=match.group()
    num=int(val)+1
    return str(num)
info=re.sub(r'\d+',add1,str)
print info
#literal books=1001

Why did it go wrong ？ Baidu for a while , I saw a foreign website saying

You are redefining what str()

means. str is the built-in Python name of the string type, and you
don’t want to change it.Use a different name for the local variable,
and remove the global statement.

Translation means ,str() It comes with the system , You can't define another name by yourself when using it str The variable of , It's going to conflict .

So I put the customized str The variable was changed to another name ,str1, The code passes .

This is because if I customize my name str The variable of ,str It will be recognized by the system as a string conversion function , Such a function is passed into sub In the parameters of the function ,is not callable, in other words , Is not callable . Check whether your code has similar errors ？

The reason for the error 2

stay Python in , A function is actually an object , And all functions are callable objects . A class instance can also become a callable object , Only need to implement a special way __call__().

therefore , When an error is reported XXX is not callable When , It is likely that you are calling a variable or object that cannot be called , The specific performance is that you call the function 、 Wrong way of variable .

Link to the original text ：https://blog.csdn.net/lifelegendc/article/details/55051374