How to avoid leaking the loop index into namespace for python 2.x?

Question

for i in mylist:
    process(i)

[process(j) for j in mylist]

At the end of the execution, i and j remain in the namespace with the last value of mylist.

Other than creating a specialized function to hide i from leaking; what are other ways to hide loop indexes ?

Answer 1

there is not much else you can do except explicitly deleting i and j:

for i in mylist:
    process(i)

[process(j) for j in mylist]

print j, i  # -> 8 8
del i, j
print j, i  # NameError: name 'j' is not defined

a side note: if the list is empty, the variable remains undefined:

for i in []:
    pass
print i  # NameError: name 'i' is not defined

and one more thing: in python 2.x variables from list-comprehensions (not generator expressions though) are leaked as well; in python 3.x this is a NameError.

[i for i in range(3)]
print i  #  2