Python syntax for an empty while loop
Asked Answered
U

2

47

I have written this:

    while file.readline().startswith("#"):
        continue

But I suspect the continue is unnecessary? What is the correct syntax for what i'm trying to achieve?

Unbiased answered 10/2, 2013 at 11:6 Comment(2)
When I do this sort of thing I have a generator that skips commented lines and just yields the good lines. Whereas your use case seems to be for skipping the comments at the head of a file.Tinctorial
In this simple example pass and continue are equivalent. I'd favour continue however as it expresses your intent more clearly.Lupine
G
76
while file.readline().startswith("#"):
    pass

This uses the pass statement :

The pass statement does nothing. It can be used when a statement is required syntactically but the program requires no action.

http://www.network-theory.co.uk/docs/pytut/passStatements.html

Garv answered 10/2, 2013 at 11:7 Comment(0)
S
1

Accepted answer link to pass statement tutorial is no longer working see official docs here:

https://docs.python.org/3/tutorial/controlflow.html#pass-statements

pass is a null operation — when it is executed, nothing happens. It is useful as a placeholder when a statement is required syntactically, but no code needs to be executed

Shifty answered 23/5, 2022 at 1:44 Comment(0)

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