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We all know how to join things up for output in Python 2.6.

>>> words = ['a', 'list', 'of', 'words']
>>> numbers = 1, 2, 3, 4, 5
>>> print ' '.join(words)
a list of words
>>> print ' + '.join(str(n) for n in numbers)
1 + 2 + 3 + 4 + 5

String.join does the joining (without any unwanted extra spaces). I often create a bound method, which I think looks a little better:

>>> spaced = ' '.join
>>> concat = ''.join
>>> spaced(words)
'a list of words'
>>> concat(words)
'alistofwords'

String.join() hasn’t changed in Python 3.0, but print has.

print ' '.join(words)
print ' + '.join(str(n) for n in numbers)

Applying the 2to3 converter to the snippet above gives

print(' '.join(words))
print(' + '.join(str(n) for n in numbers))

Alternatively, we can dispense with the explicit string.join. With some argument unpacking, Python 3.0’s new print function can do it all for us. It also stringifies the printed arguments, so we don’t need the str(n)’s either.

print(*words)
print(*numbers, sep=' + ')

Sys.stdout is the defaulted destination for the print calls above. Supply a file (or anything with a write(string) method) to print elsewhere. If you’re using Python 2.6 but would like to use Python 3.0 style printing, use a future statement.

>>> from __future__ import print_function
>>> print(*[1, 2, 3, 4, 5], sep=' + ')
1 + 2 + 3 + 4 + 5
>>> print(1, 2, 3, 4, 5, sep=' + ')
1 + 2 + 3 + 4 + 5