+ Addition

Adds the left value to the right:

>>> lvariable = 5
>>> sum = lvariable + 3
>>> sum
8

− Subtraction

Subtracts the right value from left:

>>> lvariable = 5
>>> difference = lvariable - 3
>>> difference
2

* Multiplication

Multiplies left value by right:

>>> lvariable = 5
>>> product = lvariable * 3
>>> product
15

/ Division

Divides left value by right. Integer divided by integer returns an integer. Right-side value can not be zero:

>>> quotient = 5 / 3 # integer/integer
>>> quotient
1
>>> quotient = 5.2 / 3.1 # float/float
>>> quotient
1.6774193548387097
>>> quotient = 3.14159 / 7 # float/integer
>>> quotient
0.44879857142857144
>>> quotient = 7 / 3.14159 # integer/float
>>> quotient
2.2281710853421357
>>> quotient = 5 / 0
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ZeroDivisionError: integer division or modulo by zero

% Modulus

Divides left value by right and returns the remainder:

>>> remainder = 5 % 3
>>> remainder
2
>>> remainder = 3 % 5
>>> remainder
3

** Exponent

Left value raised to the power of the right:

>>> exp = 2 ** 3
>>> exp
8
>>> exp = 2.1 ** 3
>>> exp
9.261000000000001

// Floor Division

Division, but with the decimal values rounded down to the nearest integer:

>>> quotient = 5.2 // 3.1
>>> quotient
1.0

==

Checks to see if left variable is equal to right. Please note that when using floating point numbers (floats) that there will be times that the calculations do not act as you might expect due to the way floating point numbers are stored in Python. When you need precise calculations, use the decimal library:

>>> print(a == b)
False
>>> test = 1.1+2.2
>>> test == 3.3
False # test is actually 3.3000000000000003

== (Strings)

Comparison of strings, lists, and other objects is very similar to that of numbers:

Str1 = "This is a test"
Str2 = "This was a test"
Str1 == Str2
False
Lst1 = [1,2,3,4]
Lst2 = Lst1
Lst2 == Lst1
True

!=

Checks to see if left variable is NOT equal to right (3.x and 2.x):

Python 2.x
 >>> print(a != b)
 True
Python 3.x
 >>> print(a != b)
 True

<>

Checks to see if left variable is NOT equal to right (2.x only):

Python 2.x
 >>> print(a <> b)
 True
Python 3.x (use !=)
 >>> print(a <> b)
 File "<stdin>", line 1
 print(a <> b)
 ^
 SyntaxError: invalid syntax

>

Checks to see if left variable is greater than right:

>>> print(a > b)
True

<

Checks to see if left variable is less than right:

>>> print(a < b)
False

>=

Checks to see if left variable is greater than or equal to right:

>>> print(a >= b)
True

<=

Checks to see if left variable is less than or equal to right:

>>> print(a <= b)
False

=

Assignment operator. Assigns the value on right to variable on left:

>>> a = 3
>>> a
3

+=

Add and assign or increment operator. Adds value on right to left variable:

>>> a = 3
>>> a += 3
>>> a
6

−=

Subtract and assign or decrement operator. Subtracts value on right from left variable:

>>> a = 3
>>> a -= 2
>>> a
1

*=

Multiply and assign. Multiplies right value to left value:

>>> a = 3
>>> a *= 2
>>> a
6

/=

Divide and assign. Divides right value from left value:

>>> a = 3
>>> a /= 2.0
>>> a
1.5

%=

Modulus and assign:

>>> a = 3
>>> a %= 2
>>> a
1

**=

Exponent and assign:

>>> a = 3
>>> a **= 2
>>> a
9

//=

Floor Division and assign:

>>> a = 5.0
>>> a //= 3.0
>>> a
1.0

and

Logical AND – if both values are True (or in many cases, nonzero), then returns a true value:

a = 0
b = 8
if (a and b):
    print 'true'
else:
    print 'false'

False

or

Logical OR – if either value is True, returns a true value:

a = 0
b = 8
if (a or b):
    print 'true'
else:
    print 'false'
True

not

Logical NOT – reverses the operator. True becomes False and False becomes True:

a = 0
b = 8
if not(a and b):
    print 'true'
else:
    print 'false'
True

In

Returns True if x is in y:

>>> a = "This is the time"
>>> 'is' in a
True
>>> lst = [1,2,4,7,9]
>>> 2 in lst
True
>>> 8 in lst
False

not in

Returns True if x is NOT in y:

>>> a = "This is the time"
>>> 'frog' not in a
True

is

Returns True if variables on each side refers to the same object:

>>> c = list(['a','b','c'])
>>> d = c
>>> c is d
True

is not

Returns False if variables on each side refers to the same object:

>>> c = list(['a','b','c'])
>>> d = c
>>> c is not d
False

&

Binary AND

Compares bit by bit the two values; if the bits are both 1 in any given position, then the result is 1 for that bit position:

>>> a & b
8 (00001000)
00011000
00001000
Equals
00001000 (8)

|

Binary OR

Compares bit by bit the two values and if either of the bits are 1 in any given position, then the result is 1 for that bit position:

>>> a | b
24 (00011000)
00011000
00001000
Equals
00011000 (24)

^

Binary XOR.

Compares bit by bit the two values and if either of the bits are 1 but not both bits, then the result is 1 for that bit position:

>>> a ^ b
16 (00010000)
00011000
00001000
Equals
00010000 (16)

∼

Binary Ones complement.

Ones complement is defined as the value that is obtained by inverting all the bits in the number. This then behaves like a negative value of the original value in some arithmetic operations:

a = 24 (00011000)
>>> ∼a
-25
(11100111)

<<

Binary Shift Left.

Shifts all bits to the left. Zeros are inserted at the right side:

>>> a << 2
96 (00011000 Shift Left 2 = 01100000 = 64 + 32 = 96)

>>

Binary Shift Right.

Shifts all bits to the right by x positions. Zeros are inserted at the left side:

>>> a >> 2
6 (00011000 Shift Right 2 = 00000110 = 2 + 4 = 6)