How to remove a word from a list with a specific character in a specific index position

Question

this is what I have so far:

wlist = [word for word in wlist if not any(map(lambda x: x in word, 'c'))]

this code works, however in its current state it will remove all strings from wlist which contain 'c'. I would like to be able to specify an index position. For example if

wlist = ['snake', 'cat', 'shock']
wlist = [word for word in wlist if not any(map(lambda x: x in word, 'c'))]

and I select index position 3 than only 'shock' will be removed since 'shock' is the only string with c in index 3. the current code will remove both 'cat' and 'shock'. I have no idea how to integrate this, I would appreciate any help, thanks.

mozway · Answer 1 · 2022-12-07T20:11:45.560

1

Simply use slicing:

out = [w for w in wlist if w[3:4] != 'c']

Output: ['snake', 'cat']

edited Dec 07 '22 at 20:11

answered Dec 07 '22 at 20:10

mozway

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how about checking multiple indexes? – I'mahdi Dec 07 '22 at 20:11
@I'mahdi OP has asked for a single index (3) – Pranav Hosangadi Dec 07 '22 at 20:12
@I'mahdi use multiple slices? – mozway Dec 07 '22 at 20:12
@PranavHosangadi, Yes, I know, but this is very simple and in my opinion can not use for complex problem. with my solution can use only in [3, 7, 10, 20] but with this ?! for example if op wants index 3, 7, 10, 20, ... – I'mahdi Dec 07 '22 at 20:13
2

Slicing is an elegant way to avoid the error if `len(w) < 4` – Pranav Hosangadi Dec 07 '22 at 20:14
2

@I'mahdi why not? `positions = [0, 3] ; [w for w in wlist if all(w[i:i+1] != 'c' for i in positions)]` – mozway Dec 07 '22 at 20:16
@mozway, exactly a simple solution for a complex problem can be a very complex form ;) – I'mahdi Dec 07 '22 at 20:18

score 0 · Answer 2 · answered Dec 07 '22 at 20:11

0

Probably you should use regular expressions. How ever I don`t know them )), so just iterates through list of words.

for i in wlist:
try:
    if i[3] == 'c':
        wlist.remove(i)
except IndexError:
    continue

answered Dec 07 '22 at 20:11

Adolf Tulenkov

1

1

Don't remove from a list while iterating over it – Pranav Hosangadi Dec 07 '22 at 20:13
@PranavHosangadi Yes, you are right, sometimes I just implement the first solution that comes to mind without even thinking, sorry. – Adolf Tulenkov Dec 07 '22 at 20:21

milanbalazs · Answer 3 · 2022-12-07T20:34:07.777

You should check only the 3rd character in your selected string. If you use the [<selected_char>:<selected_char>+1] list slicing then only the selected character will be checked. More about slicing: https://stackoverflow.com/a/509295/11502612

Example code:

checking_char_index = 3
wlist = ["snake", "cat", "shock", "very_long_string_with_c_char", "x", "c"]
out = [word for word in wlist if word[checking_char_index : checking_char_index + 1] != "c"]
print(out)

As you can see, I have extended your list with some corner-case strings and it works as expected as you can see below.

Output:

>>> python3 test.py 
['snake', 'cat', 'very_long_string_with_c_char', 'x', 'c']

How to remove a word from a list with a specific character in a specific index position

3 Answers3