16.9: Variables and Parameters Are Local
- Page ID
- 16904
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When you create a variable inside a function, it is local, which means that it only exists inside the function. For example:
def cat_twice(part1, part2): cat = part1 + part2 print_twice(cat)
This function takes two arguments, concatenates them, and prints the result twice. Here is an example that uses it:
>>> line1 = 'Bing tiddle ' >>> line2 = 'tiddle bang.' >>> cat_twice(line1, line2) Bing tiddle tiddle bang. Bing tiddle tiddle bang.
When cat_twice
terminates, the variable cat
is destroyed. If we try to print it, we get an exception:
>>> print cat NameError: name 'cat' is not defined
Parameters are also local. For example, outside print_twice
, there is no such thing as bruce
.