[andreasvc]

To avoid str() calls with concatenation, use % formatting:

    '%s %s' % ('hello', 'world')

Avoiding these implicit behaviors helps avoid bugs; it's worth it.

I'd recommend going for Python 3 unless there's a specific reason (library) keeping you on 2.

[andybak]

I'd recommend:

    '{} {}'.format('hello', 'world')

But yes - either way - it solves the need to do str() when concatenating.

[andreasvc]

I never understood the need for the new style of formatting, or the advantage. Fortunately % formatting is no longer getting deprecated.

[pyre]

The only downside that I've come across is when you do something like:

  "%s %s" % blah

If a bug causes `blah` to be a string (rather than a tuple or a list), it will attempt to expand the string, possibly giving a confusing error.