filter -package:base -package:containers -package:unordered-containers -package:pipes is:exact -package:hedgehog -package:vector -package:rio

O(n) filter, applied to a predicate and a ByteString, returns a ByteString containing those characters that satisfy the predicate.

O(n) filter, applied to a predicate and a ByteString, returns a ByteString containing those characters that satisfy the predicate.

O(n) filter, applied to a predicate and a ShortByteString, returns a ShortByteString containing those characters that satisfy the predicate.

O(n) filter, applied to a predicate and a Text, returns a Text containing those characters that satisfy the predicate.

O(n) filter, applied to a predicate and a stream, returns a stream containing those characters that satisfy the predicate. Properties

unstream . filter p . stream = filter p

Filter all keys/values that satisfy some predicate.

Keep only values in the stream passing a given predicate. Subject to fusion

Keep only values in the stream passing a given predicate. Subject to fusion Since 0.3.0

Filter all values that satisfy some predicate.

filter (> "a") (fromList [(5,"a"), (3,"b")]) == singleton 3 "b"
filter (> "x") (fromList [(5,"a"), (3,"b")]) == empty
filter (< "a") (fromList [(5,"a"), (3,"b")]) == empty

Filter all elements that satisfy some predicate.

filter p xs removes any elements from xs that do not satisfy p.

filter, applied to a predicate and a list, returns the list of those elements that satisfy the predicate; i.e.,

filter p xs = [ x | x <- xs, p x]

>>> filter odd [1, 2, 3]
[1,3]

filter, applied to a predicate and a list, returns the list of those elements that satisfy the predicate; i.e.,

filter p xs = [ x | x <- xs, p x]

Examples

>>> filter odd [1, 2, 3]
[1,3]

>>> filter (\l -> length l > 3) ["Hello", ", ", "World", "!"]
["Hello","World"]

>>> filter (/= 3) [1, 2, 3, 4, 3, 2, 1]
[1,2,4,2,1]

Drops chunks from an input stream if they fail to match a given filter predicate. See filter. Items pushed back to the returned stream are propagated back upstream. Example:

ghci> Streams.fromList ["the", "quick", "brown", "fox"] >>=
Streams.filter (/= "brown") >>= Streams.toList
["the","quick","fox"]

Skip elements of a stream that fail a predicate

filter given a predicate returns a sequence of all elements that satisfy the predicate.

> filter (< 5) [1 .. 10]
[1,2,3,4]

Keep all values that satisfy the given predicate

>>> filter even (fromList [("C",3),("B",2),("A",1)])
fromList [("B",2)]

>>> filter odd (fromList [("C",3),("B",2),("A",1)])
fromList [("C",3),("A",1)]

Remove characters from ShortText which don't satisfy given predicate.

>>> filter (`notElem` ['a','e','i','o','u']) "You don't need vowels to convey information!"
"Y dn't nd vwls t cnvy nfrmtn!"

filter (const False) t == ""

filter (const True) t == t

length (filter p t) <= length t

filter p t == pack [ c | c <- unpack t, p c ]

Only allows Word8s to pass if they satisfy the predicate