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31 lines
996 B
Markdown
31 lines
996 B
Markdown
# Two Ways To Find An Item In A List
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The `List` module has the typical `find` function that you'd expect any
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enumerable type to include. It has a very similar `find_opt` function as
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well. The difference is in the return types.
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When using `List.find` you'll have to deal with the possibility of a
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`Not_found` exception.
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```reasonml
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switch (List.find(item => item.id == id, my_list)) {
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| exception Not_found => print_endline("Not found!")
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| item => print_endline("Found it: " ++ item.name)
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}
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```
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The `List.find_opt` function has a more familiar interface that doesn't
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require you to know the details of what exceptions could arise. All you want
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to know is if it was found or _not_. This is achieved by having an
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`option('a)` return type.
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```reasonml
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switch (List.find_opt(item => item.id == id, my_list)) {
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| None => print_endline("Not found!")
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| Some(item) => print_endline("Found it: " ++ item.name)
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}
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```
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See the [`List` module](https://reasonml.github.io/api/List.html) for more
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details.
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