Python: Removing a last element from list of list?

Question

Given a List A . I want to remove the last element ( b,'zz') of each list with list A .

A = [ [(a,'rr'),(c,'rr'),(d,'rr'),(b,'zz')],
      [(g,'rr'),(h,'rr'),(e,'rr'),(b,'zz')],
      [(c,'rr'),(r,'rr'),(s,'rr'),(b,'zz')] ]

What I tried.

for i in A:
    N = del i[-1]

But it is not working.

Answer 1

You can use the list.pop() method:

for i in A:
    i.pop()

Reference: https://docs.python.org/2/tutorial/datastructures.html

Answer 2

你可以简单地切片直到列表理解中的最后一项：

A = [l[:-1] for l in A]

Answer 3

del is a statement and must be used accordingly. Most importantly, it cannot be used in an assignment.

Simply remove the assignment:

for i in A:
  del i[-1]