CODEWITHSUNDEEP
pythonfunctionvariablesgloballocal
user6397534
user6397534

Reputation:

How can i check if there is a global or local variable

I want to check if that variable exists and print it if it does.

x = 10 

def example(): 

z = 5

print("X (Global variable) : ",x) 
print("Z (example() : ",z)

example() 

print(z)

When i add print(z) it will obviously raises an error because there is no variable called z.

Thanks for the answers guys. (specially Jasper, kevin and icantcode)

x = 10 
def example(): 

z = 5

example() 


try:
    print(z)
except NameError:
    print("There is no global variable called Z! ")

Upvotes: 4

Views: 13141

Answers (3)

Tadhg McDonald-Jensen
Tadhg McDonald-Jensen

Reputation: 21464

The most straight forward way would be to try to use it and if it fails do something else:

try:
    something_with(z)
except NameError:
    fallback_code()

But this could potentially fail because something_with doesn't exist or has a typo/bug in it so the NameError you catch may be unrelated to the z variable.

you could also check dictionaries of locals() and globals() (and builtins module if you want to go that deep)

# import builtins
if 'z' in locals() or 'z' in globals(): # or hasattr(builtins, 'z'):
    print(z)
else:
    fallback_code()

Upvotes: 4

ICantCode
ICantCode

Reputation: 33

try:
    print(z)
 except NameError:
    print("No variable named z!")

This code try's to print z and if there is no variable named z, it will run the code under except.

Upvotes: -1

Jared Goguen
Jared Goguen

Reputation: 9008

The built-in methods locals() and globals() return a dictionary of local/global variable names and their values.

if 'z' in locals():
    print(z)

Upvotes: 6

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