Assuming 'a' is a list that contains (for example) [2,4,2,3,3,3]
for i in a:
if a.count(i) == i:
a.remove(i)
How can I convert the code to one line using list comprehenstion, lambda, filter or something diffrent.
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Matthias
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Help Pleasee
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No, my goal is to remove only one of the N elemnts that got N numbers. – Help Pleasee Dec 16 '16 at 11:57
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For example, if a is [2,3,3,2,4,4] the output will be: [2,3,3,4,4] because only 2 got N elemnts as N (two elemnts of two) . – Help Pleasee Dec 16 '16 at 11:58
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@HelpPleasee that kind of information is best in your question. – Paul Rooney Dec 16 '16 at 11:58
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And what exactly is `N`? You really need to edit your question to make it clear just what you are asking. – Rory Daulton Dec 16 '16 at 12:00
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And you want this as a one-liner... why? Is it a homework assignment? – DisappointedByUnaccountableMod Dec 16 '16 at 12:05
1 Answers
2
Never remove items from a list while iterating over it, the iteration gets messed up and you won't get the desired result.
>>> [x for i, x in enumerate(a) if a.count(x) != x or a.index(x) != i]
[4, 2, 3, 3]
Alex Hall
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For ecample, if a is [2,3,3,2,4,4] the output will be: [2,3,3,4,4] because only 2 got N elemnts as N (two elemnts of two) – Help Pleasee Dec 16 '16 at 11:56
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@HelpPleasee so you actually do want to remove just one of each of the relevant values, i.e. what I had guessed you didn't want? – Alex Hall Dec 16 '16 at 11:58
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HallIn your answer, all the values that got N elemnts got deleted, not only one – Help Pleasee Dec 16 '16 at 11:59
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@HelpPleasee OK I've edited the answer. However it's O(n^2) which is very slow. Is it important to remove the *first* occurrence of these numbers, or is it OK to remove any one? For example is `[2, 4, 3, 3]` acceptable output? – Alex Hall Dec 16 '16 at 12:10