Dynamic concatenated string creation in Python

Question

So I'm creating a 'Aussie' ballot app and I'm looking for a creative solution to an input prompt.

Basically the user inputs how many people, and then submits up to 1000 votes or w/e.

Assuming 3 candidates the input prompt would look something like:

ballot = raw_input('1 for %s: 2 for %s: 3 for %s: ') % (cand_list[0], cand_list[1], cand_list[2])

But what I'd really like to come up with is a dynamic prompt (assume the user enters 5, 10, w/e number of candidates)

I've looked into separating the ballot assignment and printing, or creating a ballot string entirely separate and passing it(assuming I can make some kind of stringbuilder function), but I'm curious to see other approaches. Still tinkering with it to see if I'll need to escape the % formatting.

Python Stringbuilder(sort of) and More string concat

score 3 · Answer 1 · answered Nov 08 '13 at 18:22

3

Something like this using string formatting, str.join and enumerate:

>>> candidates = ['foo', 'bar', 'spam']
>>> print ' : '.join('{} for {}'.format(i, c) for i, c in enumerate(candidates, 1))
1 for foo : 2 for bar : 3 for spam

>>> candidates = ['foo', 'bar', 'spam', 'python', 'guido']
>>> print ' : '.join('{} for {}'.format(i, c) for i, c in enumerate(candidates, 1))
1 for foo : 2 for bar : 3 for spam : 4 for python : 5 for guido

answered Nov 08 '13 at 18:22

Ashwini Chaudhary

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why zip range instead of `enumerate(canidates,1)`? – Joran Beasley Nov 08 '13 at 18:24
works great! i'll tinker with getting the newline after the enumeration – crownedzero Nov 08 '13 at 18:50

score 0 · Answer 2 · answered Nov 08 '13 at 18:18

0

Construct your format string separately in stages:

inner_format_string = "{num} for %s: "
full_format_string = " ".join(inner_format_string.format(num=i) for i in xrange(1, len(cand_list) + 1))

ballot = raw_input(full_format_string % tuple(cand_list))

answered Nov 08 '13 at 18:18

spencer nelson

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Joran Beasley · Answer 3 · 2013-11-08T18:30:30.353

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canidates = ["Frank","Bill","Joe","Suzy"]
raw_input(", ".join("Enter %d For %s"%(num,canidate) for num,canidate in enumerate(canidates,1)))

perhaps

edited Nov 08 '13 at 18:30

answered Nov 08 '13 at 18:19

Joran Beasley

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almost perfect, just have to prevent a new line after each candidate – crownedzero Nov 08 '13 at 18:29

Dynamic concatenated string creation in Python

3 Answers3