CODEWITHSUNDEEP
python
user17833823
user17833823

Reputation:

while, for loop difference in the following Python codes

I'd like to know the difference between the following two codes using while and for loop in each.

I want to pop elements of the list sandwich_orders into the list of finished_sandwich. it seems to work with while loop but not with for loop. What mistake did I make?

sandwich_orders = ['chicken sandwich', 'beef sandwich', 'avocado sandwich', 'pork sandwich']
finished_sandwich = []

while sandwich_orders:
    cur_sandwich = sandwich_orders.pop()
    finished_sandwich.append(cur_sandwich)
print (finished_sandwich)

for cur_sandwich in sandwich_orders:
    cur_sandwich = sandwich_orders.pop()
    finished_sandwich.append(cur_sandwich)
print (finished_sandwich)

Upvotes: 0

Views: 79

Answers (2)

SAI SANTOSH CHIRAG
SAI SANTOSH CHIRAG

Reputation: 2084

After while loop, your variable sandwich_orders becomes empty as you are popping elements from it during the while loop. So you need to reinitialize it.Try in this way

sandwich_orders = ['chicken sandwich', 'beef sandwich', 'avocado sandwich', 'pork sandwich']
finished_sandwich = []

while sandwich_orders:
    cur_sandwich = sandwich_orders.pop()
    finished_sandwich.append(cur_sandwich)
print (finished_sandwich)

sandwich_orders = ['chicken sandwich', 'beef sandwich', 'avocado sandwich', 'pork sandwich']    
finished_sandwich= []

for cur_sandwich in sandwich_orders:
    finished_sandwich.append(cur_sandwich)
print (finished_sandwich)

Upvotes: 0

Adon Bilivit
Adon Bilivit

Reputation: 26925

The for loop could be written thus:

sandwich_orders = ['chicken sandwich', 'beef sandwich', 'avocado sandwich', 'pork sandwich']
finished_sandwich = []

for _ in sandwich_orders[:]:
  finished_sandwich.append(sandwich_orders.pop())

...or, to retain the order of the original list:

for _ in sandwich_orders[:]:
      finished_sandwich.insert(0, sandwich_orders.pop())

...or, to avoid loops altogether:

finished_sandwich = sandwich_orders[:]

Upvotes: 1

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