Is it possible to define global variables in a function in Python

Question

How do I declare a global variable in a function in Python?

That is, so that it doesn't have to be declared before but can be used outside of the function.

Answer 1

Yes, but why?

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def a():     globals()['something'] = 'bob' 

Answer 2

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def function(arguments):     global var_name     var_name = value #must declare global prior to assigning value 

This will work in any function, regardless of it is in the same program or not.

Here's another way to use it:

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def function():     num = #code assigning some value to num     return num 

NOTE: Using the return built-in will automatically stop the program (or the function), regardless of whether it is finished or not.

You can use this in a function like this:

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if function()==5 #if num==5:     #other code 

This would allow you to use the variable outside of the function. Doesn't necessarily have to be declared global.

In addition, to use a variable from one function to another, you can do something like this:

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import primes as p #my own example of a module I made p.prevPrimes(10) #generates primes up to n for i in p.primes_dict:     if p.primes_dict[i]: #dictionary contains only boolean values         print p.primes_dict[i] 

This will allow you to use the variable in another function or program without having use a global variable or the return built-in.