global — Expert Playground

Declares a variable inside a function as belonging to the global scope

Python Playground

import dis

x = 10

def without_global():
    y = x + 1  # LOAD_GLOBAL for x
    return y

def with_global():
    global x
    x = x + 1  # LOAD_GLOBAL + STORE_GLOBAL
    return x

def with_local():
    x = 20     # STORE_FAST (local)
    return x   # LOAD_FAST (local)

print("Reading global (no declaration needed):")
dis.dis(without_global)
print("\nWriting global (needs 'global'):")
dis.dis(with_global)
print("\nLocal variable:")
dis.dis(with_local)

Output

Click "Run" to execute your code

Global reads use LOAD_GLOBAL, global writes use STORE_GLOBAL. Local variables use LOAD_FAST/STORE_FAST which are faster because they use indexed array access instead of dict lookup.

Challenge

Try modifying the code above to explore different behaviors. Can you extend the example to handle a new use case?

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