When I loop over one list I use:
for item in items:
print item
but often I want to loop through two lists at once, and I've been doing
this like I would in any other language - creating an index counter and
incrementing it.
For example, (completely arbitrary), I have two strings of the same
length, and I want to return a string which, at each character
position, has the letter closest to 'A' from each of the original
strings:
def lowest(s1,s2):
s = ""
for i in xrange(len(s1)):
s += lowerChar(s1[i],s2[i])
return s
this seems unpythonic, compared to something like:
def lowest(s1,s2):
s = ""
for c1,c2 in s1,s2:
s += lowerChar(c1,c2)
return s
this doesn't work - s1,s2 becomes a tuple. Is there a way to do this
that I'm missing? I don't see it in the docs.
This works:
def lowest(s1,s2):
s = ""
for c1,c2 in [x for x in zip(s1,s2)]:
s += lowerChar(c1,c2)
return s
but it's hardly any more elegant than using a loop counter, and I'm
guessing it's performance is a lot worse - I assume that the zip
operation is extra work?
Iain
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