Ned Deily added the comment:
It may be hard to see what's going on with the code written as a list
comprehension. We could expand it out to something roughly equivalent and
print the first n iterations:
def main():
lista =[1, 4, 5 , 5, 6 , 3 ,1]
def ins(x):
return lista.insert(x,0)
for idx, v in enumerate(lista):
if v == 5:
ins(idx)
print(idx, lista)
if idx > 10:
break
if __name__ == '__main__':
main()
(2, [1, 4, 0, 5, 5, 6, 3, 1])
(3, [1, 4, 0, 0, 5, 5, 6, 3, 1])
(4, [1, 4, 0, 0, 0, 5, 5, 6, 3, 1])
(5, [1, 4, 0, 0, 0, 0, 5, 5, 6, 3, 1])
(6, [1, 4, 0, 0, 0, 0, 0, 5, 5, 6, 3, 1])
(7, [1, 4, 0, 0, 0, 0, 0, 0, 5, 5, 6, 3, 1])
(8, [1, 4, 0, 0, 0, 0, 0, 0, 0, 5, 5, 6, 3, 1])
(9, [1, 4, 0, 0, 0, 0, 0, 0, 0, 0, 5, 5, 6, 3, 1])
(10, [1, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 5, 6, 3, 1])
(11, [1, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 5, 6, 3, 1])
Because the list is mutating by inserting the 0 before the 5, once the 5 entry
is found, it keeps "moving" to the right so the loop never terminates and lista
keeps expanding until Python runs out of memory. Don't do that!
----------
nosy: +ned.deily
resolution: -> not a bug
stage: -> resolved
status: open -> closed
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue22075>
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