CODEWITHSUNDEEP
haskell
Dakota Trotter
Dakota Trotter

Reputation: 310

Remove Blank Entries in List

Let's say that I declare a variable in GHCI

let a = ["hello","goodbye","","sup","bye","hi","cat","dog"]

And I want to go about removing that pesky "" from the list. From my understanding, I should be able to use dropWhile to do so, like this

dropWhile null a

But this doesn't remove the pesky "". Why is this? How can I fix this issue?

Ah, now I understand. I completely misunderstood how dropWhile works. So then to make this question a little different - how do I remove blank entries in a list?

Upvotes: 1

Views: 830

Answers (1)

awesoon
awesoon

Reputation: 33671

dropWhile drops elements while given predicate is True. null "hello" is False, so, it should'n drop anything.

You are probably looking for a filter:

Prelude> filter (not . null) ["hello","goodbye","","sup","bye","hi","cat","dog"]
["hello","goodbye","sup","bye","hi","cat","dog"]

Upvotes: 10

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