CODEWITHSUNDEEP
pythonarrays
user3815919
user3815919

Reputation:

Trying to iterate over specific column in python array

I'm trying to create a list of dictionaries in an array format. Initially I would like the first row and column to have

{'score' : 0, 'pointer' : 'none'}

in each cell, however my for loops do not seem to be carrying this out.
Here is what I have so far:

mymatrix = [[0 for x in range(len(seq1)+1)]for x in range(len(seq2)+1)]

mymatrix[0][0] = {'score' : 0, 'pointer' : 'none'}

for x in mymatrix[0][:]:
    x = {'score' : 0, 'pointer' : 'none'}
for y in mymatrix[:][0]:
    y = {'score' : 0, 'pointer' : 'none'}

for row in mymatrix:
    print row

Where seq1 and seq2 are strings.

Upvotes: 0

Views: 310

Answers (2)

parchment
parchment

Reputation: 4002

You already wrote two for loops in your list comprehension, you can just reuse them.

(I modified your list comprehension, I used y and x instead of 2 x)

seq1 = 'asdfasdfasdf'
seq2 = 'asdfasdfasdf'

mymatrix = [[0 for y in range(len(seq1)+1)]for x in range(len(seq2)+1)]
#              ^^^^^^^^^^^^^^^^^^^^^^^^^^ reuse this


d = {'score' : 0, 'pointer' : 'none'}

for y in range(len(seq1)+1):
    mymatrix[0][y] = d.copy()

# The first one is already covered, just leave it off using slice
for x in range(len(seq2)+1)[1:]:
    mymatrix[x][0] = d.copy()

for line in mymatrix:
    print(line)

Out: 

[{'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}, {'pointer': 'none', 'score': 0}]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[{'pointer': 'none', 'score': 0}, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Upvotes: 1

TheSoundDefense
TheSoundDefense

Reputation: 6935

As far as I can tell, the problem is here:

x = {'score' : 0, 'pointer' : 'none'}

This line of code isn't going to mutate the actual matrix. All you're doing here is reassigning the value of the name x, which is not inherently bound to the matrix you're trying to change. You need to directly reference the matrix. Try this instead:

for xind, x in enumerate(mymatrix[0][:]):
  mymatrix[0][xind] = {'score' : 0, 'pointer' : 'none'}

Upvotes: 0

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