Removing items from a list while preserving order in python3



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-1















How can I remove items from a list but keep its original order?
Using remove() seems to mess the order up.



Let's say for example a list like this:



['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']


How can i remove the words "book" and "tree" without messing up the order?










share|improve this question



















  • 2





    It totally doesn't.

    – John Zwinck
    Nov 15 '18 at 7:53











  • remove doesnt change the order

    – Stef van der Zon
    Nov 15 '18 at 8:08






  • 1





    do not iterate a list while removing stuff from it ... then you do not get messed up.

    – Patrick Artner
    Nov 15 '18 at 8:12

















-1















How can I remove items from a list but keep its original order?
Using remove() seems to mess the order up.



Let's say for example a list like this:



['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']


How can i remove the words "book" and "tree" without messing up the order?










share|improve this question



















  • 2





    It totally doesn't.

    – John Zwinck
    Nov 15 '18 at 7:53











  • remove doesnt change the order

    – Stef van der Zon
    Nov 15 '18 at 8:08






  • 1





    do not iterate a list while removing stuff from it ... then you do not get messed up.

    – Patrick Artner
    Nov 15 '18 at 8:12













-1












-1








-1








How can I remove items from a list but keep its original order?
Using remove() seems to mess the order up.



Let's say for example a list like this:



['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']


How can i remove the words "book" and "tree" without messing up the order?










share|improve this question
















How can I remove items from a list but keep its original order?
Using remove() seems to mess the order up.



Let's say for example a list like this:



['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']


How can i remove the words "book" and "tree" without messing up the order?







python python-3.x list






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 15 '18 at 8:23









Patrick Artner

26.4k62544




26.4k62544










asked Nov 15 '18 at 7:50









AstudentAstudent

608




608







  • 2





    It totally doesn't.

    – John Zwinck
    Nov 15 '18 at 7:53











  • remove doesnt change the order

    – Stef van der Zon
    Nov 15 '18 at 8:08






  • 1





    do not iterate a list while removing stuff from it ... then you do not get messed up.

    – Patrick Artner
    Nov 15 '18 at 8:12












  • 2





    It totally doesn't.

    – John Zwinck
    Nov 15 '18 at 7:53











  • remove doesnt change the order

    – Stef van der Zon
    Nov 15 '18 at 8:08






  • 1





    do not iterate a list while removing stuff from it ... then you do not get messed up.

    – Patrick Artner
    Nov 15 '18 at 8:12







2




2





It totally doesn't.

– John Zwinck
Nov 15 '18 at 7:53





It totally doesn't.

– John Zwinck
Nov 15 '18 at 7:53













remove doesnt change the order

– Stef van der Zon
Nov 15 '18 at 8:08





remove doesnt change the order

– Stef van der Zon
Nov 15 '18 at 8:08




1




1





do not iterate a list while removing stuff from it ... then you do not get messed up.

– Patrick Artner
Nov 15 '18 at 8:12





do not iterate a list while removing stuff from it ... then you do not get messed up.

– Patrick Artner
Nov 15 '18 at 8:12












2 Answers
2






active

oldest

votes


















3














You are probably iterating your list while trying to figure out if you need to remove something - you never iterate a list that you want to insert/remove from - its a recipe for disaster.



Instead create a new list:



a = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
b = [e for e in a if e not in "book","tree"]

print(b)


Output:



['house', 'ambulance', 'window', 'Dragonball', 'alfa']





share|improve this answer























  • This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

    – Astudent
    Nov 15 '18 at 8:17



















3














You could just use remove() since it doesn't change list order.



It is often best to just create a new object item like this:



item_list = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
item_list = [e for e in item_list if e not in ('book', 'alfa')]





share|improve this answer























  • This is the true. Sorry for the poorly edited question.

    – Astudent
    Nov 15 '18 at 8:19











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









3














You are probably iterating your list while trying to figure out if you need to remove something - you never iterate a list that you want to insert/remove from - its a recipe for disaster.



Instead create a new list:



a = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
b = [e for e in a if e not in "book","tree"]

print(b)


Output:



['house', 'ambulance', 'window', 'Dragonball', 'alfa']





share|improve this answer























  • This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

    – Astudent
    Nov 15 '18 at 8:17
















3














You are probably iterating your list while trying to figure out if you need to remove something - you never iterate a list that you want to insert/remove from - its a recipe for disaster.



Instead create a new list:



a = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
b = [e for e in a if e not in "book","tree"]

print(b)


Output:



['house', 'ambulance', 'window', 'Dragonball', 'alfa']





share|improve this answer























  • This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

    – Astudent
    Nov 15 '18 at 8:17














3












3








3







You are probably iterating your list while trying to figure out if you need to remove something - you never iterate a list that you want to insert/remove from - its a recipe for disaster.



Instead create a new list:



a = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
b = [e for e in a if e not in "book","tree"]

print(b)


Output:



['house', 'ambulance', 'window', 'Dragonball', 'alfa']





share|improve this answer













You are probably iterating your list while trying to figure out if you need to remove something - you never iterate a list that you want to insert/remove from - its a recipe for disaster.



Instead create a new list:



a = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
b = [e for e in a if e not in "book","tree"]

print(b)


Output:



['house', 'ambulance', 'window', 'Dragonball', 'alfa']






share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 15 '18 at 8:13









Patrick ArtnerPatrick Artner

26.4k62544




26.4k62544












  • This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

    – Astudent
    Nov 15 '18 at 8:17


















  • This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

    – Astudent
    Nov 15 '18 at 8:17

















This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

– Astudent
Nov 15 '18 at 8:17






This was it. If I had posted the full program I have, it might have been easier for experienced people to understand the problem. My bad, I tried to simplify the problem too much! Thank you!

– Astudent
Nov 15 '18 at 8:17














3














You could just use remove() since it doesn't change list order.



It is often best to just create a new object item like this:



item_list = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
item_list = [e for e in item_list if e not in ('book', 'alfa')]





share|improve this answer























  • This is the true. Sorry for the poorly edited question.

    – Astudent
    Nov 15 '18 at 8:19















3














You could just use remove() since it doesn't change list order.



It is often best to just create a new object item like this:



item_list = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
item_list = [e for e in item_list if e not in ('book', 'alfa')]





share|improve this answer























  • This is the true. Sorry for the poorly edited question.

    – Astudent
    Nov 15 '18 at 8:19













3












3








3







You could just use remove() since it doesn't change list order.



It is often best to just create a new object item like this:



item_list = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
item_list = [e for e in item_list if e not in ('book', 'alfa')]





share|improve this answer













You could just use remove() since it doesn't change list order.



It is often best to just create a new object item like this:



item_list = ['book', 'house', 'tree', 'ambulance', 'window', 'Dragonball', 'alfa']
item_list = [e for e in item_list if e not in ('book', 'alfa')]






share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 15 '18 at 8:13









Stef van der ZonStef van der Zon

519211




519211












  • This is the true. Sorry for the poorly edited question.

    – Astudent
    Nov 15 '18 at 8:19

















  • This is the true. Sorry for the poorly edited question.

    – Astudent
    Nov 15 '18 at 8:19
















This is the true. Sorry for the poorly edited question.

– Astudent
Nov 15 '18 at 8:19





This is the true. Sorry for the poorly edited question.

– Astudent
Nov 15 '18 at 8:19

















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