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pythonstringmatrix
Jeff
Jeff

Reputation: 45

Python - string to matrix representation

  1. I have a string a="1 2 3; 4 5 6". How do i express this as a matrix [1 2 3; 4 5 6] in Python?
  2. I want to then use another such string b, convert to a matrix and find a x b.

Upvotes: 0

Views: 25232

Answers (2)

heinst
heinst

Reputation: 8786

This is one way to do it, split the string at ;, then go through each string, split at ' ' and then go through that, convert it to an int and append to a sublist, then append that sublist to another list:

a = "1 2 3; 4 5 6"

aSplit = a.split('; ')

l = []

for item in aSplit:
    subl = []
    for num in item.split(' '):
        subl.append(int(num))
    l.append(subl)

print l

Upvotes: 2

Cory Kramer
Cory Kramer

Reputation: 117856

You can use the numpy module to create a matrix directly from a string in matlab type format

>>> import numpy as np
>>> a="1 2 3; 4 5 6"
>>> np.matrix(a)
matrix([[1, 2, 3],
        [4, 5, 6]])

You can use the same library to do matrix multiplication

>>> A = np.matrix("1 2 3; 4 5 6")
>>> B = np.matrix("2 3; 4 5; 6 7")
>>> A * B
matrix([[28, 34],
        [64, 79]])

Go read up on the numpy library, it is a very powerful module to do all of the type of work that you are referring to.

Upvotes: 4

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