foldl' -package:base is:exact -package:unordered-containers -package:vector -package:rio
foldl' is like foldl, but strict in the accumulator.
O(n) A strict version of
foldl.
A strict version of
foldl. Each application of
the operator is evaluated before using the result in the next
application. This function is strict in the starting value.
A strict version of
foldl. Each application of
the operator is evaluated before using the result in the next
application. This function is strict in the starting value.
A strict version of
foldl. Each application of
the operator is evaluated before using the result in the next
application. This function is strict in the starting value.
A strict version of
foldl. Each application of
the operator is evaluated before using the result in the next
application. This function is strict in the starting value.
Left-associative fold of a structure but with strict application of
the operator.
This ensures that each step of the fold is forced to Weak Head Normal
Form before being applied, avoiding the collection of thunks that
would otherwise occur. This is often what you want to strictly reduce
a finite structure to a single strict result (e.g.
sum).
For a general
Foldable structure this should be semantically
identical to,
foldl' f z = foldl' f z . toList
Strict left fold of the metadatas
Strict left fold over all key-value pairs in the headers map.
Example:
ghci> :set -XOverloadedStrings
ghci> import Data.Monoid
ghci> let hdrs = H.fromList [("Accept", "text/plain"), ("Accept", "text/html")]
ghci> let f (cntr, acc) _ val = (cntr+1, val <> ";" <> acc)
ghci> H.foldl' f (0, "") hdrs
(2,"text/html;text/plain;")
Left-associative fold of a structure but with strict application of
the operator.
This ensures that each step of the fold is forced to weak head normal
form before being applied, avoiding the collection of thunks that
would otherwise occur. This is often what you want to strictly reduce
a finite list to a single, monolithic result (e.g.
length).
For a general
Foldable structure this should be semantically
identical to,
foldl' f z = foldl' f z . toList
Left associative/strict push fold. foldl' reduce initial
stream invokes reduce with the accumulator and the next
input in the input stream, using initial as the initial value
of the current value of the accumulator. When the input is exhausted
the current value of the accumulator is returned. Make sure to use a
strict data structure for accumulator to not build unnecessary lazy
expressions unless that's what you want. See the previous section for
more details.
Strict left associative fold.
Left fold over bytes, strict in the accumulator.
Left fold over all bytes in the chunks, strict in the accumulator.
Left-associative fold of a structure but with strict application of
the operator.
This ensures that each step of the fold is forced to weak head normal
form before being applied, avoiding the collection of thunks that
would otherwise occur. This is often what you want to strictly reduce
a finite list to a single, monolithic result (e.g.
length).
For a general
Foldable structure this should be semantically
identical to,
foldl f z = foldl' f z . toList
Left fold.
Benchmarks show that folding is actually Pretty Damn Slow™: consider
whether folding is really the best thing to use in your scenario.
'foldl\'' is like
foldl, but strict in the accumulator.