Python Programming for Biology: Bioinformatics and Beyond

Constructor

(numpy.)

Description

Example

array(data,

dtype)

Creates a numeric array object from another

array or array-like data. All values will be

converted to the same data type. Data type will

be inferred from the input values if not

specifically stated. An array may have more

than one dimension/axis, e.g. constructed using

a list of lists.

a = array([[1,

2, 3],

[4, 5, 6]])

a.shape #

(2,3) – rows,

cols

a.ndim # 2 -

axes

a.tolist() #

Make Python

list

b =

array([3.0, 0,

4.7, 1],

float)

# Floats: 3.0,

0.0, 4.7, 1.0

matrix(data,

dtype)

Creates a numeric matrix object from an array

or array-like data. Provides an alternative to

array() that has more matrix-oriented

operations, e.g. multiplication is not element-

wise. Data type will be inferred from the input

values if not specifically stated.

m1 =

matrix([[1,2],

[1,0]])

m2 =

matrix([[3,0],

[0,3]])

print(m1 * m2)

# matrix([[3,

6],

#

[3, 0]])