2D list in python

[weblover]

Hi,

i have a 2D list in python which i'm trying to fill using 2 for loops. but the problem is when i finish the filling procedure and i print the values, i find that they are not arrangeed in the order of input.

def funcdist(myarr):        
    diffs = 0
    testarr = []
    finarr = []
    for hx in range(len(myarr)):
        del testarr[:]
        for hy in range(len(myarr)):
            diffs=0
            for ch1, ch2 in zip(myarr[hx], myarr[hy]):
                if ch1 != ch2:
                    diffs += 1
            testarr.append(diffs)
        finarr.append((testarr))
    return finarr

in this case their should be some 0's in the diagonal, but when i print the array after i finish, i found that the 0's are all on the right side of the array. why this is happening?

and another question, how to add a column of 1 as the first column of the array?? i have no idea on how to do this.

Thank you

[weblover]

i managed to add a column of 1 using insert in numpy but still the problem of input order is not fixed ..

[Gribouillis]

This should work

def funcdist(myvar):
    return [[ sum(1 for (a, b) in zip(line_a, line_b) if a != b)
            for line_b in myarr] for line_a in myarr ]

The problem in your snippet, is that a new testarr needs to be created in the hx loop. Replace line 6 by line 3 and discard line 3.

[weblover]

it works now, thank you. but can you please explain to me what's the difference ??

[Gribouillis]

The difference is that in your first version, the same list object testarr is appended to finarr at line 13. In the end, all the lines in finarr are a single list object containing the values appended at the last iteration.

[weblover]

ok, now i get it.. thank you. problem solved