filter -package:conduit -package:pipes -package:ghc
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 p xs removes any elements from
xs that
do not satisfy
p.
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 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 all values that satisfy the 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
The
filter function takes a predicate
p
and a sequence
xs and returns a sequence of those elements
which satisfy the predicate.
Filter all elements 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 ByteString,
returns a ByteString containing those characters that satisfy the
predicate.
Filter all keys/values that satisfy some predicate.
O(n) Drop all elements that do not satisfy the predicate.
Drop elements which do not satisfy the predicate
Drop elements which do not satisfy the predicate
O(n) Drop all elements that do not satisfy the predicate.
O(n) Drop all elements that do not satisfy the predicate.
O(n) Drop all elements that do not satisfy the predicate.
O(n) Drop all elements that do not satisfy the predicate.
Filter this map by retaining only elements which values
satisfy a predicate.
Filter this set by retaining only elements satisfying a
predicate.
Generates a value that satisfies a predicate.
Shrinks of the generated value will also satisfy the predicate. From
the original generator's shrink tree, any values that fail the
predicate will be removed, but any subsequent shrinks that satisfy it
will be retained. Compared to
filter, shrinking may be slower
but will be optimal.
It's possible that the predicate will never pass, or will only pass at
a larger size than we're currently running at. To avoid looping
forever, we limit the number of retries, and grow the size with each
retry. If we retry too many times then the whole generator is
discarded.