Python string formatting with percent sign

Question

I am trying to do exactly the following:

>>> x = (1,2)
>>> y = 'hello'
>>> '%d,%d,%s' % (x[0], x[1], y)
'1,2,hello'

However, I have a long x, more than two items, so I tried:

>>> '%d,%d,%s' % (*x, y)

but it is syntax error. What would be the proper way of doing this without indexing like the first example?

Answer 1

str % .. accepts a tuple as a right-hand operand, so you can do the following:

>>> x = (1, 2)
>>> y = 'hello'
>>> '%d,%d,%s' % (x + (y,))  # Building a tuple of `(1, 2, 'hello')`
'1,2,hello'

Your try should work in Python 3, where Additional Unpacking Generalizations is supported, but not in Python 2.x:

>>> '%d,%d,%s' % (*x, y)
'1,2,hello'