Removing a certain word from a list

Question

I have had to put items into a list but because I did not know how many items it would be I had to set the list up as

matching_words=["none"]*100

Once all the words have been added, I then want the remaining "none"'s to be removed so the list is only as long as the number of words added is. How can this be done. I tried this

newMatching_words=matching_words.remove("ABCDEFG")
print(newMatching_words)

This returned

None

Forget about C, this is Python! You do not need to define list's length before. — Elis Byberi, Nov 22 '17 at 15:22
You just create a list in python and add elements as you go. There is no need to declare its size. — Anudeep Bulla, Nov 22 '17 at 15:23
When ever I have attempted it the result was - matching_words was out of index — R watt, Nov 22 '17 at 15:24
you need to use the `append` method. E.g. `matching_words.append("Something")` — Roars, Nov 22 '17 at 15:24
maybe this will help https://stackoverflow.com/a/5944754/2180506 — Pedro Henrique, Nov 22 '17 at 15:26
Also if you do need to remove something. You can use the remove method without having to assign the result to a new variable. Instead you would use `matching_words.remove("Something")` and then you can just `print(matching_words)` — Roars, Nov 22 '17 at 15:27

quamrana · Answer 1 · 2017-11-22T15:32:43.167

4

You should have started with an empty list and appended items to it:

matching_words = []

for word in source_of_words:
    matching_words.append(word)

print(matching_words)

Also, just so you know about the remove method:

print(matching_words)

matching_words.remove('bar')

print(matching_words)

Sample Output:

['foo', 'bar', 'baz']
['foo', 'baz']

edited Nov 22 '17 at 15:32

answered Nov 22 '17 at 15:24

quamrana

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score 0 · Answer 2 · answered Nov 22 '17 at 15:47

There are some things which i want to explain when you need to define list length and when you don't.

First, you don't need to define list length at the beginning in general case:

You can simply do :

#Just for example

new_list=[]

for i in map(chr,range(97,101)):
    new_list.append(i)

print(new_list)

output:

['a', 'b', 'c', 'd']

Yes you need to define a empty list when you have another list for index items like this:

matching_words=[None]*10

index_list=[4,3,1,2]

for i in zip(list(map(chr,range(97,101))),index_list):
    matching_words.insert(i[1],i[0])

print(matching_words)

output:

[None, 'c', 'd', None, None, 'b', None, 'a', None, None, None, None, None, None]
['c', 'd', 'b', 'a']

In this program we have to insert chracter in that order in which the index_list showing the intergers , so if we try without defining list before then as you can see we are inserting first chr at index 4 which is not there.

In your case if you have second situation then try this to remove rest of none:

print([i for i in matching_words if i!='none'])

otherwise if you should go with first case.

Removing a certain word from a list

2 Answers2