Python Programming for Biology: Bioinformatics and Beyond

Comparison operators

The  following  table  lists  the  standard  item  comparison  operations  that  are  built  into

Python,  to  compare  the  value  or  identity  of  objects.  Note  that  in  Python  3  inequality

comparisons can only be made on objects of a comparable type. In Python 2 you can make

the  comparison  2  <  ‘a’  (even  though  it  does  not  really  make  sense)  but  this  is  illegal  in

Python 3.

Operator

Description

Example

==

Tests whether two operands (either side of the

operator) have the same value, giving True if

they do and False otherwise.

x = 3 * 5

if x == 15:

print("Equal")

!=

Tests whether two operands have different

values, giving True if they do and False

otherwise.

seq = 'GCGC'

if seq !=

'TATA':

print("Not

equal")

>

Tests whether the value of the first operand is

greater in value than the second, giving True if

it is and False otherwise.

x = 2**10

x > 1024

Evaluates to False;

2

10

is exactly

1024, not greater.

<

Tests whether the value of the first operand is

smaller in value than the second, giving True if

it is and False otherwise.

x = 2**10

x < 1025

Evaluates to True.

---

>=

Tests whether the value of the first operand is