String formatting: % vs. .format vs. string literal

Question

Python 2.6 introduced the str.format() method with a slightly different syntax from the existing % operator. Which is better and for what situations?

Pyt

Answer 1

Assuming you're using Python's logging module, you can pass the string formatting arguments as arguments to the .debug() method rather than doing the formatting yourself:

log.debug("some debug info: %s", some_info)

which avoids doing the formatting unless the logger actually logs something.