23 lines
771 B
OCaml
23 lines
771 B
OCaml
# let find_index pred lst =
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let rec loop n = function
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[] -> raise Not_found
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| x::xs -> if pred x then n
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else loop (n+1) xs
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in
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loop 0 lst;;
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val find_index : ('a -> bool) -> 'a list -> int = <fun>
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# let haystack =
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["Zig";"Zag";"Wally";"Ronald";"Bush";"Krusty";"Charlie";"Bush";"Bozo"];;
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val haystack : string list =
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["Zig"; "Zag"; "Wally"; "Ronald"; "Bush"; "Krusty"; "Charlie"; "Bush";
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"Bozo"]
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# List.iter (fun needle ->
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try
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Printf.printf "%i %s\n" (find_index ((=) needle) haystack) needle
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with Not_found ->
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Printf.printf "%s is not in haystack\n" needle)
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["Washington"; "Bush"];;
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Washington is not in haystack
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4 Bush
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- : unit = ()
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