Very basic formatting Issue

Question

If I have a list such as the following:

[(10, 20), (50, 60), (100, 110)]

How could I make this look like this:

'10-20,50-60,100-110'

if the number of pairs in my list is variable?

I am sorry for such an easy question. But every thing I have tried such as replacing the ',' with a '-' has failed. Any ideas?

score 5 · Accepted Answer · answered Apr 28 '12 at 01:47

5

>>> x = [(10, 20), (50, 60), (100, 110)]
>>> ','.join('-'.join(map(str, t)) for t in x)
'10-20,50-60,100-110'

answered Apr 28 '12 at 01:47

Dan D.

Could I do this 'string'+'|'+(','.join('-'.join(map(str, t)) for t in x)) and get string|10-20,50-60,100-110?? – Peter Hanson Apr 28 '12 at 01:50
1

@PatrickCampbell, Yes, you could also do `'string|%s' % ','.join('-'.join(map(str, t)) for t in x)` to avoid string concatentation. – huon Apr 28 '12 at 01:52
Could you help me with a similar question here please?! http://stackoverflow.com/questions/10359993/going-to-a-certain-position-in-a-string – Peter Hanson Apr 28 '12 at 02:34

score 2 · Answer 2 · answered Apr 28 '12 at 02:00

2

Another (somewhat more readable) way to do this formatting is to use either

A) % style string formatting:

data = [(10, 20), (50, 60), (100, 110)]

fmt = "%d-%d, %d-%d, %d-%d" % (data[0][0], data[0][1], data[1][0], data[1][1],...)

or, with a list comprehension:

fmt = ",".join("%d-%d" % i for i in data)

B) The python string.format method:

fmt = ",".join("{0}-{1}".format(*i) for i in data)

answered Apr 28 '12 at 02:00

Joel Cornett

Thanks Joel, could you look here to see what I was talking about before: http://stackoverflow.com/questions/10359993/going-to-a-certain-position-in-a-string – Peter Hanson Apr 28 '12 at 02:07
^^I cannot get this to work, I think you can make a simple fix – Peter Hanson Apr 28 '12 at 02:31
@PatrickCampbell: It works perfectly fine for me. What, specifically, can you not get to work? – Joel Cornett Apr 28 '12 at 02:35
It gives me the error saying 'starts' is not defined and ends the program – Peter Hanson Apr 28 '12 at 02:36

score 1 · Answer 3 · answered Apr 28 '12 at 01:45

1

Is this what your looking for?

data = [(10, 20), (50, 60), (100, 110)]
for x in data:
    print x[0], "-", x[1]

answered Apr 28 '12 at 01:45

Lostsoul

Yes, something very close. However, I want to add that to a string I already have. So what would I do if I had string+????? – Peter Hanson Apr 28 '12 at 01:47
1

I'm not sure how your program is structured but instead of print you could append the result to your existing string? or if you merge later in your program you can make a list with the data being printed and then append it later on – Lostsoul Apr 28 '12 at 01:48

score 0 · Answer 4 · answered Apr 28 '12 at 02:25

0

You can unpack the values of the list while iterating over it within a comprehension:

>>> x = [(10, 20), (50, 60), (100, 110)]
>>> ','.join('%d-%d' % (y,z) for (y,z) in x)
'10-20,50-60,100-110'

answered Apr 28 '12 at 02:25

Jeff

4 Answers4