python - How to pass tuple1 if ... else tuple2 to str.format? -

put simply, why following error?

>>> yes = true >>> 'no [{0}] yes [{1}]'.format((" ", "x") if yes else ("x", " ")) traceback (most recent call last):   file "<stdin>", line 1, in <module> indexerror: tuple index out of range 

i use python 2.6.

☞ indexing option:

when accessing arguments’ items in format string, should use index call value:

yes = true print 'no [{0[0]}] yes [{0[1]}]'.format((" ", "x") if yes else ("x", " ")) 

{0[0]} in format string equals (" ", "x")[0] in calling index of tulple

{0[1]} in format string equals (" ", "x")[1] in calling index of tulple

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☞ * operator option:

or can use * operator unpacking argument tuple.

yes = true print 'no [{0}] yes [{1}]'.format(*(" ", "x") if yes else ("x", " ")) 

when invoking * operator, 'no [{0}] yes [{1}]'.format(*(" ", "x") if yes else ("x", " ")) equals 'no [{0}] yes [{1}]'.format(" ", "x") if if statement true

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☞ ** operator option (it's method when var dict):

yes = true print 'no [{no}] yes [{yes}]'.format(**{"no":" ", "yes":"x"} if yes else {"no":"x", "yes":" "})