Format string with all elements of a list

Question

words = [\'John\', \'nice\', \'skateboarding\']
statement = \"%s you are so %s at %s\" % w for w in words

produces

File \"

        

Answer 1

Two things are wrong:

• You cannot create a generator expression without parenthesis around it. Simply putting w for w in words is invalid syntax for python.

• The % string formatting operator requires a tuple, a mapping or a single value (that is not a tuple or a mapping) as input. A generator is not a tuple, it would be seen as a single value. Even worse, the generator expression would not be iterated over:

  >>> '%s' % (w for w in words)
  ' at 0x108a08730>'
  

So the following would work:

statement = "%s you are so %s at %s" % tuple(w for w in words)

Note that your generator expression doesn't actually transform the words or make a selection from the words list, so it is redundant here. So the simplest thing is to just cast the list to a tuple instead:

statement = "%s you are so %s at %s" % tuple(words)