This is also known as the string *formatting* or *interpolation* operator.
Given ``format % values`` (where *format* is a string), ``%`` conversion
specifications in *format* are replaced with zero or more elements of *values*.
-The effect is similar to using the :c:func:`sprintf` in the C language.
+The effect is similar to using the :c:func:`sprintf` function in the C language.
+For example:
+
+.. doctest::
+
+ >>> print('%s has %d quote types.' % ('Python', 2))
+ Python has 2 quote types.
If *format* requires a single argument, *values* may be a single non-tuple
object. [5]_ Otherwise, *values* must be a tuple with exactly the number of