Python detects whether a variable has a defined method

The examples in this article describe how Python detects a variable's definition. Share to everyone for your reference. as follows:

The first method uses the built-in function locals ():

' TestVar ' in Locals (). Keys ()

The second method uses the built-in function dir ():

' TestVar ' in Dir ()

The third method uses the built-in function VARs ():

VARs (). Has_key (' TestVar ')

The test is as follows:

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#testvar未定义 in [1]: ' TestVar ' in locals (). The keys () out[1]: false in [2]: ' TestVar ' in Dir () out[2]: False in [3]: VARs (). has _key (' TestVar ') out[3]: False #定义testvar in [4]: Testvar=1 in [5]: "TestVar ' in Locals" (). Keys () out[5]: True in [6]: ' Test var ' in Dir () Out[6]: true in [7]: VARs (). Has_key (' TestVar ') out[7]: True

There is also the use of try...except ... own definition, in short, a lot of methods.

I hope this article will help you with your Python programming.