Reading matrix from a text file and storing it in an array

Question

Defintion

I have the following matrix stored in a text file:

 1 0 0 1 0 1 1
 0 1 0 1 1 1 0
 0 0 1 0 1 1 1

I want to read this matrix from the text tile and store it in a 2D array using python 2.7.

Code I attempted

The code I attempted is as follows:

f = open('Matrix.txt')
triplets=f.read().split()
for i in range(0,len(triplets)): triplets[i]=triplets[i].split(',')
A = np.array(triplets, dtype=np.uint8)

print(A)

Problem

As it stands the code above is printing the matrix in a 1D manner. Is it possible to save the matrix in a 2D manner as defined in the matrix above?

Possible duplicate of How to print multiple lines of text with python — user177800
– user177800, Commented Jul 3, 2018 at 19:28
Give us the code which has at least no syntax error. How are you splitting by , as I cannot see in the matrix example? Missing : in for loop and indentation. Possible solution: List of lists can be interpreted as a 2-D matrix. — mad_
– mad_, Commented Jul 3, 2018 at 19:33

sacuL · Accepted Answer · 2018-07-03 19:34:22Z

4

Use np.loadtxt:

A = np.loadtxt('filename.txt')

>>> A
array([[ 1.,  0.,  0.,  1.,  0.,  1.,  1.],
       [ 0.,  1.,  0.,  1.,  1.,  1.,  0.],
       [ 0.,  0.,  1.,  0.,  1.,  1.,  1.]])

Alternatively, you could read it line by line similarly to what you were doing (but this isn't efficient):

A = []
with open('filename.txt', 'r') as f:
    for line in f:
        A.append(list(map(int,line.split())))

>>> np.array(A)
array([[1, 0, 0, 1, 0, 1, 1],
       [0, 1, 0, 1, 1, 1, 0],
       [0, 0, 1, 0, 1, 1, 1]])

edited Jul 3, 2018 at 19:34

answered Jul 3, 2018 at 19:27

sacuL

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1 Comment

Anthony Over a year ago

thank you so much man! From all the solutions online yours is by far the simplest :)

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