CODEWITHSUNDEEP
pythonalgorithm
adolfosrs
adolfosrs

Reputation: 9389

What is the easier way to initialize a matrix in Python?

I'm working in a 2D matrix with a simple polynomial algorithm:

for i in range(len(content1)):
    for j in range(len(content2)):
        if content1[i]==content2[j]:
            matrix[i][j]=1
        else:
            matrix[i][j]=0

This code itself do not compile for a simple reason. dot_matrix is not initialized. So what is the easier way to do that?

Also, how could I implement the same logic I'm using above in a one lined code like this:

matrix = [[0 for x in range(len(content1))] for x in range(len(content2))]

Upvotes: 2

Views: 85

Answers (2)

Cocksure
Cocksure

Reputation: 235

For one thing, you're using content1 as the outer index in the first chunck of code, so matric should be initialized with content1 on the outer as well:

matrix = [[0 for x in range(len(content2))] for x in range(len(content1))]

And yes, you can do it in one line like the other answer mentions:

matrix = [[1 if i == j else 0 for j in content2] for i in content1]

Upvotes: 2

aecolley
aecolley

Reputation: 2011

Replace the xs with i and j, then replace the 0 with (1 if content1[i]==content2[j] else 0).

Upvotes: 1

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