Question

I’m having some issues filling a list in Python. I keep getting a list index out of range error. The output of len(network) is 7 so I figured filling it from 0-6 should work to give me a 7×7 list.

def fillNodeTable():
  nodeTable = []
  for x in xrange(0, (len(network) -1)):
    for y in xrange(0, (len(network) -1)):
      nodeTable[x][y].append(Node)
  print nodeTable

So I ended up with this and it works

n = len(network)
nodeTable = [[Node]*n for x in xrange(n)]

When I print the nodeTable to debug I get the following:

<class __main__.Node at 0xb737914c>

Is this just because I’m appending a class to each entry or have I done something else wrong here?

Answer 1

I think you are porting a MATLAB code. You are getting the out of range error on nodeTable. You initialize it to an empty array.

Try something like this, or use the array classes in numpy:

> a = []
>>> for i in xrange(3):
...     a.append([])
...     for j in xrange(3):
...             a[i].append(i+j)

or

n = 7
a = [[0]*n for x in xrange(n)]