Removing items from a list while preserving order in python3
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
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
asked Nov 15 '18 at 7:50
AstudentAstudent
538
add a comment |
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
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
asked Nov 15 '18 at 7:50
AstudentAstudent
538
2
It totally doesn't.
– John Zwinck
Nov 15 '18 at 7:53
remove doesnt change the order
– van der Zon Stef
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
add a comment |
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
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
asked Nov 15 '18 at 7:50
AstudentAstudent
538
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
python python-3.x list
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
asked Nov 15 '18 at 7:50
AstudentAstudent
538
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
asked Nov 15 '18 at 7:50
AstudentAstudent
538
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
edited Nov 15 '18 at 8:23
Patrick Artner
23.1k62343
23.1k62343
asked Nov 15 '18 at 7:50
AstudentAstudent
538
asked Nov 15 '18 at 7:50
AstudentAstudent
538
asked Nov 15 '18 at 7:50
AstudentAstudent
538
538
2
It totally doesn't.
– John Zwinck
Nov 15 '18 at 7:53
remove doesnt change the order
– van der Zon Stef
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
add a comment |
2
It totally doesn't.
– John Zwinck
Nov 15 '18 at 7:53
remove doesnt change the order
– van der Zon Stef
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
– van der Zon Stef
Nov 15 '18 at 8:08
remove doesnt change the order
– van der Zon Stef
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
add a comment |
2 Answers
2
active
oldest
votes
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']
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
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
add a comment |
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')]
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
This is the true. Sorry for the poorly edited question.
– Astudent
Nov 15 '18 at 8:19
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
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']
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
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
add a comment |
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']
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
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
add a comment |
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']
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
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']
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
answered Nov 15 '18 at 8:13
Patrick ArtnerPatrick Artner
23.1k62343
23.1k62343
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
add a comment |
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
add a comment |
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')]
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
This is the true. Sorry for the poorly edited question.
– Astudent
Nov 15 '18 at 8:19
add a comment |
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')]
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
This is the true. Sorry for the poorly edited question.
– Astudent
Nov 15 '18 at 8:19
add a comment |
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')]
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
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')]
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
answered Nov 15 '18 at 8:13
van der Zon Stefvan der Zon Stef
44110
44110
This is the true. Sorry for the poorly edited question.
– Astudent
Nov 15 '18 at 8:19
add a comment |
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
add a comment |
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2
It totally doesn't.
– John Zwinck
Nov 15 '18 at 7:53
remove doesnt change the order
– van der Zon Stef
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