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printing a two dimensional array in python

I have to print this python code in a 5x5 array the array should look like this :

0 1 4 (infinity) 3
1 0 2 (infinity) 4
4 2 0  1         5
(inf)(inf) 1 0   3
3 4 5   3        0

can anyone help me print this table? using indices.

for k in range(n):
        for i in range(n):
            for j in range(n):
                if A[i][k]+A[k][j]<A[i][j]:
                    A[i][j]=A[i][k]+A[k][j]
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1 Answer

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by (71.8m points)

A combination of list comprehensions and str joins can do the job:

inf = float('inf')
A = [[0,1,4,inf,3],
     [1,0,2,inf,4],
     [4,2,0,1,5],
     [inf,inf,1,0,3],
     [3,4,5,3,0]]

print('
'.join([''.join(['{:4}'.format(item) for item in row]) 
      for row in A]))

yields

   0   1   4 inf   3
   1   0   2 inf   4
   4   2   0   1   5
 inf inf   1   0   3
   3   4   5   3   0

Using for-loops with indices is usually avoidable in Python, and is not considered "Pythonic" because it is less readable than its Pythonic cousin (see below). However, you could do this:

for i in range(n):
    for j in range(n):
        print '{:4}'.format(A[i][j]),
    print

The more Pythonic cousin would be:

for row in A:
    for val in row:
        print '{:4}'.format(val),
    print

However, this uses 30 print statements, whereas my original answer uses just one.


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