String substitution in Python 3?

Question

I\'m trying to do something like this:

subs = \'world\'
\"Hello {[subs]}\"

in Python 3.

I can\'t quite figure out the syntax (having co

Answer 1

The % operator will work, the syntax for which is simple:

>>> subs = 'world'
>>> 'Hello %s' % subs
'Hello world'

The new syntax for string formatting allows for additional options, heres a snippet from the python docs overviewing the basic ways to use the newer str.format() method:

>>> '{0}, {1}, {2}'.format('a', 'b', 'c')
'a, b, c'
>>> '{}, {}, {}'.format('a', 'b', 'c')  # 2.7+ only
'a, b, c'
>>> '{2}, {1}, {0}'.format('a', 'b', 'c')
'c, b, a'
>>> '{2}, {1}, {0}'.format(*'abc')      # unpacking argument sequence
'c, b, a'
>>> '{0}{1}{0}'.format('abra', 'cad')   # arguments' indices can be repeated
'abracadabra'

So using the newer syntax, a simple resolution to your problem would be:

>>> subs = 'world'
>>> 'Hello {}'.format(subs)
'Hello world'