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Elm Complete Course / Lists & Collections

List.foldl

Learn List.foldl in Elm with a construct-specific explanation, a unique example, a practical boundary, and a mastery check.

10 min read • Intermediate

List.foldl is an atomic Elm topic inside Lists & Collections. The example below uses the actual construct named by the lesson rather than a generic placeholder.

Focus on what List.foldl changes: the input, binding, control path, object state, collection, runtime effect, or language contract. Then alter one value and verify that the behavior changes for a reason specific to this feature.

Topic-specific example

elm-04-03-list-foldl.elm
elm Try It Live
List.foldl (+) 0 [ 4, 5, 6 ]
Edge case / engineering note

Check the input collection shape, whether the operation mutates or returns a new value, and what happens for an empty collection.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content