Python range function - stop step is function

Question

Simple question that likely due to keywords, lead to an explanation on the function itself rather than clarification on whether or not the following is the case:

When using the range function to loop, with a function as the stop step, eg

for item in range(some_function()):
    #do something

is the result of the function call stored for use or evaluated at each step?

I'd imagine its the former but it agitates that I can't confirm.

Answer 1

There is nothing special about range here. The behavior is defined in the language reference .

The expression list is evaluated once

The "expression list" is the part after the in (ie, range(some_function()) in your example). No matter what is there, it is only evaluated once.