Convert a numpy 2D array to list [duplicate]

Question

I have an array

r = np.zeros((5,6))
print r

whose output is

[[ 0.  0.  0.  0.  0.  0.]
 [ 0.  0.  0.  0.  0.  0.]
 [ 0.  0.  0.  0.  0.  0.]
 [ 0.  0.  0.  0.  0.  0.]
 [ 0.  0.  0.  0.  0.  0.]]

I want to assign the values in this array to a list so I created a list by name grid

grid1 = [['a' for i in range (0,6)]  for j in range (0,5)]
print grid1

whose output is

[['a', 'a', 'a', 'a', 'a', 'a'], ['a', 'a', 'a', 'a', 'a', 'a'], ['a', 'a', 'a', 'a', 'a', 'a'], ['a', 'a', 'a', 'a', 'a', 'a'], ['a', 'a', 'a', 'a', 'a', 'a']]

How can I assign each value in the array to the corresponding location in list using a for loop?

I am using python 2.7

Output should be:

 [[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0],[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0],[0, 0, 0, 0, 0, 0]]

So, you just want to convert a numpy 2d array to a list of lists? — awesoon
– awesoon, Commented Dec 19, 2015 at 5:42

ilyas patanam · Accepted Answer · 2015-12-19 05:48:43Z

6

import numpy as np
r = np.zeros((5,6))
lst = r.tolist()

answered Dec 19, 2015 at 5:48

ilyas patanam

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Comments

Patrick Yu · Accepted Answer · 2015-12-19 06:10:56Z

1

Another version, using for loops and two arrays, concatenating from the numpy array to the python list element by element:

listed = []
temp = []
r = np.zeros((5,6))

for i in r:
   for j in i:
     temp += [int(j)]
   listed += [temp]
   temp = []

print listed

listed returns

[
 [0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0], 
 [0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0]
]

...as expected.

edited Dec 19, 2015 at 6:10

answered Dec 19, 2015 at 6:03

Patrick Yu

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Comments

ThatPixelCherry · Accepted Answer · 2015-12-19 05:41:09Z

0

Didnt fully understand. Is this what your looking for?

numbers = []
  for array in r:
    for arrayj in array:
        numbers.append(arrayj)

answered Dec 19, 2015 at 5:41

ThatPixelCherry

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1 Comment

RoY Over a year ago

i need output in this form sir [[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0],[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0],[0, 0, 0, 0, 0, 0]] rather than [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0] which is ur codes output

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