ToshiBoy wrote:
> I have two lists A and B that are both defined as range(1,27) I want
> to find the entries that are valid for A = BxB
[ ... ]
> I get, as expected 1,4,9,16,25 printed out being the only members of B
> where the condition is true, but when I print B I get:
>
> [1, 2, 3, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25]
>
> 1 to 5 is correct, but why doesn't the remove method remove 7 and
> above? What am I doing wrong here?
Try this:
A = range(1,27)
B = range(1,27)
C = []
for b in B:
print "Trying", b
if b*b in A:
print b
C.append (b)
else:
print "Removing", b
B.remove(b)
print 'B', B
print 'C', C
The essential problem is that your `B.remove`s are pulling the rug out from
under your `for b in B:`. There are ways to mess with B while you iterate.
Running though B backwards will do: `for b in B[::-1]:`, or iterating over
a copy of B: `for b in B[:]:` or `for b in list(B):`. Leaving B alone and
building up the desired items in C is probably simplest.
Mel.
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