Python String Formatting With Dictionaries

In Python, you can use dictionaries instead of tuples to populate values via classic string formatting.

By Ryan McGreal

Posted January 04, 2012 in Blog (Last Updated January 04, 2012)

My mind is duly blown. I never realized that the traditional printf-style string formatting in Python - the kind that uses the % operator - supports the use of a dictionary as well as a tuple.

The following works:

>>> data = {
    'title': 'Python String Formatting With Dictionaries',
    'author': 'Ryan McGreal',
    'summary': 'In Python, you can use dictionaries instead of tuples to populate values via classic string formatting.',
    'content': 'My mind is duly blown...',
    'author_bio': 'Ryan McGreal lives in Hamilton with his family and works as a programmer and writer.',
}

>>> template = """


<span style="color: red">%(title)s</span>





%(title)s
By %(author)s
%(summary)s


%(content)s

%(author_bio)s



"""

>>> print template % data

As an ultra-lightweight templating engine, this is pretty sweet: it's fast, simple, supports Unicode, and has no third-party dependencies.