How to convert a list to a matrix using numpy in python ?


Examples of how to convert a list to a matrix using numpy in python:

Create a list in python

Lets consider for example the following list

l = [4,1,7,3,2]

Note: to check the type of a variable in python we can use the function type():

type(l)

which returns here:

<type 'list'>

Convert a list of numbers to a matrix

To convert a list of numbers to a matrix, as solution is to use the numpy function asarray(): illustration:

import numpy as np

A = np.asarray(l)

print(A)

gives

array([4, 1, 7, 3, 2])

and

type(A)

gives

<type 'numpy.ndarray'>

Note: to check the length of the input list:

len(l)

returns

5

end the matrix dimensions

A.shape

returns

(5,)

and the matrix type:

A.dtype

returns

dtype('int32')

Convert a list of strings to a matrix

Work also to convert a list of strings to a matrix:

  l = ['a','b','c','d','e','f']
  A = np.asarray(l)
  print(A)

gives

  array(['a', 'b', 'c', 'd', 'e', 'f'], 
    dtype='|S1')

Convert a list of strings to a matrix using numpy.array()

Amother solution using numpy.array()

import numpy as np

l = [1,2,3,4]

A = np.array(l)

returns

array([1, 2, 3, 4])

References