How to treat the last element in list differently in Python?
I need to do some special operation for the last element in a list. Is there any better way than this?
array = [1,2,3,4,5] for i, val in enumerate(array): if (i+1) == len(array): // Process for the last element else: // Process for the other element
Solution 1:
for item in list[:-1]:
print "Not last: ", item
print "Last: ", list[-1]
If you don't want to make a copy of list, you can make a simple generator:
# itr is short for "iterable" and can be any sequence, iterator, or generator
def notlast(itr):
itr = iter(itr) # ensure we have an iterator
prev = itr.next()
for item in itr:
yield prev
prev = item
# lst is short for "list" and does not shadow the built-in list()
# 'L' is also commonly used for a random list name
lst = range(4)
for x in notlast(lst):
print "Not last: ", x
print "Last: ", lst[-1]
Another definition for notlast:
import itertools
notlast = lambda lst:itertools.islice(lst, 0, len(lst)-1)
Solution 2:
If your sequence isn't terribly long then you can just slice it:
for val in array[:-1]:
do_something(val)
else:
do_something_else(array[-1])