What is the result of % in Python?


What does the % in a calculation? I can't seem to work out what it does.

Does it work out a percent of the calculation for example: 4 % 2 is apparently equal to 0. How?

2/20/2019 8:33:14 AM

Accepted Answer

The % (modulo) operator yields the remainder from the division of the first argument by the second. The numeric arguments are first converted to a common type. A zero right argument raises the ZeroDivisionError exception. The arguments may be floating point numbers, e.g., 3.14%0.7 equals 0.34 (since 3.14 equals 4*0.7 + 0.34.) The modulo operator always yields a result with the same sign as its second operand (or zero); the absolute value of the result is strictly smaller than the absolute value of the second operand [2].

Taken from http://docs.python.org/reference/expressions.html

Example 1: 6%2 evaluates to 0 because there's no remainder if 6 is divided by 2 ( 3 times ).

Example 2: 7%2 evaluates to 1 because there's a remainder of 1 when 7 is divided by 2 ( 3 times ).

So to summarise that, it returns the remainder of a division operation, or 0 if there is no remainder. So 6%2 means find the remainder of 6 divided by 2.

12/13/2010 6:39:56 PM

Somewhat off topic, the % is also used in string formatting operations like %= to substitute values into a string:

>>> x = 'abc_%(key)s_'
>>> x %= {'key':'value'}
>>> x 

Again, off topic, but it seems to be a little documented feature which took me awhile to track down, and I thought it was related to Pythons modulo calculation for which this SO page ranks highly.

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