% character marks the beginning of the conversion specifier.
Conversion flags, minimum field width, . (dot) followed by the precision.
Conversion flags may be -, indicating left alignment;
+, indicating that a sign
" ", indicating that a space should precede positive numbers;
0, indicating that the conversion should be zero-padded.
print 'Price of eggs: $%d' % 42
print 'Hexadecimal price of eggs: %x' % 42
from math import pi
print 'Pi: %f...' % pi
print 'Very inexact estimate of pi: %i' % pi
print 'Using str: %s' % 42L
print 'Using repr: %r' % 42L