5.5. Operator String Operators¶

+ - add
- - sub
* - mul
% - mod
+= - iadd
-= - isub
*= - imul
%= - imod

5.5.1. About¶

Table 5.2. String Operator Overload¶
Operator	Method
`obj + other`	`obj.__add__(other)`
`obj - other`	`obj.__sub__(other)`
`obj * other`	`obj.__mul__(other)`
`obj % other`	`obj.__mod__(other)`

`obj += other`	`obj.__iadd__(other)`
`obj -= other`	`obj.__isub__(other)`
`obj *= other`	`obj.__imul__(other)`
`obj %= other`	`obj.__imod__(other)`

5.5.2. Mod¶

% (__mod__) operator behavior for int and str:

>>> 13 % 4
1
>>>
>>> '13' % '4'
Traceback (most recent call last):
TypeError: not all arguments converted during string formatting

>>> pi = 3.1514
>>>
>>>
>>> 'String: %s' % pi
'String: 3.1514'
>>>
>>> 'Double: %d' % pi
'Double: 3'
>>>
>>> 'Float: %f' % pi
'Float: 3.151400'

>>> firstname = 'Mark'
>>> lastname = 'Watney'
>>>
>>>
>>> 'Hello %s' % firstname
'Hello Mark'
>>>
>>> 'Hello %s %s' % (firstname, lastname)
'Hello Mark Watney'
>>>
>>> 'Hello %(fname)s %(lname)s' % {'fname': firstname, 'lname': lastname}
'Hello Mark Watney'

>>> text = 'Hello %s'
>>> text %= 'Mark Watney'
>>>
>>> print(text)
Hello Mark Watney

>>> class Str:
...     def __mod__(self, other):
...         """str substitute"""
...
...         if type(other) is str:
...             ...
...         if type(other) is tuple:
...             ...
...         if type(other) is dict:
...             ...

Note, that using %s, %d, %f is currently deprecated in favor of f'...' string formatting. More information in Builtin Printing