Python: Removing list element while iterating over list [duplicate]

Answer 1

You can still use filter, moving to an outside function the element modification (iterating just once)

def do_the_magic(x):
    do_action(x)
    return check(x)

# you can get a different filtered list
filter(do_the_magic,yourList)

# or have it modified in place (as suggested by Steven Rumbalski, see comment)
yourList[:] = itertools.ifilter(do_the_magic, yourList)

Answer 2

Why not rewrite it to be

for element in somelist: 
   do_action(element)  

if check(element): 
    remove_element_from_list

See this question for how to remove from the list, though it looks like you've already seen that Remove items from a list while iterating

Another option is to do this if you really want to keep this the same

newlist = [] 
for element in somelist: 
   do_action(element)  

   if not check(element): 
      newlst.append(element)

Answer 3

Not exactly in-place, but some idea to do it:

a = ['a', 'b']

def inplace(a):
    c = []
    while len(a) > 0:
        e = a.pop(0)
        if e == 'b':
            c.append(e)
    a.extend(c)

You can extend the function to call you filter in the condition.