24 lines
633 B
Erlang
24 lines
633 B
Erlang
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%% chapter 5: maps and records
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-module(chapter5).
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-include("records.hrl").
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-export([make_urgent/1, count_characters/1]).
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%% Maps are defined with a #{ Key => Value, ... } syntax
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%% =>: update existing key or add new key
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%% :=: update existing key
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make_urgent(M) ->
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M#{status := urgent}.
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%% Valid: make_urgent(#{status => reminder, who => kyle}).
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%% Invalid: make_urgent(#{who => kyle}).
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count_characters(Str) ->
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count_characters(Str, #{}).
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count_characters([H|T], #{ H := N }=X) ->
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count_characters(T, X#{H := N + 1});
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count_characters([H|T], X) ->
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count_characters(T, X#{H => 1});
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count_characters([], X) -> X.
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