Operators in python

Operators in python

The common binary operators for arithmetic are + for addition, - for subtraction, * for multi-
plication, and / for division. As already mentioned, Python uses ** for exponentiation. Integer
division is performed so that the result is always another integer (the integer quotient):
11>>> 25/3
8
>>> 5/2
2
This is a wrinkle that you will always have to keep in mind when working with Python. To get a
more accurate answer, use the float type:
>>> 25.0/3
8.3333333333333339
>>> 5/2.0
2.5
If just one of the operands is of type float, then the result will be of type float. Here is another
example of this pitfall:
>>> 2 * * ( 1 / 2 )
1
where we wanted to compute the square root of 2 as the 12 power of 2, but the division in the
exponent produced a result of 0 because of integer division. A correct way to do this computation
is:
>>> 2**0.5
1.4142135623730951
Another useful operator is %, which is read as ”mod”. This gives the remainder of an integer
division, as in
>>> 5 % 2
1
>>> 25 % 3
1
which shows that 5 mod 2 = 1, and 25 mod 3 = 1. This operator is useful in number theory and
cryptography.
Besides the arithmetic operators we need comparison operators: <, >, <=, >=, ==, !=, <>. In order
these are read as: is less than, is greater than, is less than or equal to, is greater than or equal to,
is equal to, is not equal to, is not equal to. The result of a comparison is always a boolen value
True or False.
>>> 2 < 3
True
>>> 3 <2
False
>>> 3 <= 2
False
Note that != and <> are synonomous; either one means not equal to. Also, the operator == means
is equal to.
>>> 2 <> 3
True
>>> 2 != 3
True
>>> 0 != 0
False>>> 0 == 0
True