Question

Say I have a function foo that I want to call n times. In Ruby, I would write:

n.times { foo }

In Python, I could write:

for _ in xrange(n): foo()

But that seems like a hacky way of doing things.

My question: Is there an idiomatic way of doing this in Python?

Answer 1

The question pre-supposes that calling foo() n times is an a priori necessary thing. Where did n come from? Is it the length of something iterable? Then iterate over the iterable. As I am picking up Python, I find that I’m using few to no arbitrary values; there is some more salient meaning behind your n that got lost when it became an integer.

Earlier today I happened upon Nicklaus Wirth’s provocative paper for IEEE Computer entitled Good Ideas – Through the Looking Glass (archived version for future readers). In section 4 he brings a different slant on programming constructs that everyone (including himself) has taken for granted but that hold expressive flaws:

“The generality of Algol’s for
statement should have been a warning
signal to all future designers to
always keep the primary purpose of a
construct in mind, and to be weary of
exaggerated generality and complexity,
which may easily become
counter-productive.”

The algol for is equivalent to the C/Java for, it just does too much. That paper is a useful read if only because it makes one not take for granted so much that we so readily do. So perhaps a better question is “Why would you need a loop that executes an arbitrary number of times?”