Python Programming On Win32

More String Operations

String objects have one unique built-in operation: the %operator (modulo) with a string left argument interprets this string as a C sprintf() format string to be applied to the right argument and returns the string resulting from this formatting operation.

The right argument should be a tuple with one item for each argument required by the format string; if the string requires a single argument, the right argument may also be a single nontuple object.^[3] The following format characters are understood: %, c, s, i, d, u, o, x, X, e, E, f, g, G. Width and precision may be a * to specify that an integer argument specifies the actual width or precision. The flag characters -, +, blank, #, and 0 are understood. The size specifiers h, l, or L may be present but are ignored. The %s conversion takes any Python object and converts it to a string using str() before formatting it. The ANSI features %p and %n aren’t supported. Since Python strings have an explicit length, %s conversions don’t assume that \0 is the end of the string.

For safety reasons, floating-point precisions are clipped to 50; %f conversions for numbers whose absolute value is over 1e25 are replaced by %g conversions.^[4] All other errors raise exceptions.

If the right argument is a dictionary (or any kind of mapping), the formats in the string must have a parenthesized key into that dictionary inserted immediately after the % character, and each format then formats the corresponding entry from the mapping. ...