Editing Idiom 52 : Check if map contains value

Idiom

# 52 Check if map contains value

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Lead paragraph

Determine whether map _m contains an entry with value _v, for some key.

Implementation

Language

Perl

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Last edited by

Imports

Code

print "Found it!" if exists $m{$v};

Documentation URL

Original attribution URL

Online demo

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Other implementations

import java.util.Map;

m.containsValue(v)

func containsValue(m map[K]T, v T) bool {
	for _, x := range m {
		if x == v {
			return true
		}
	}
	return false
}

Demo

use std::collections::BTreeMap;

let does_contain = m.values()
        .find(|&val| *val == v)
        .is_some();

Demo

import std.algorithm;

m.byValue.canFind(v);

m.containsValue(v);

v in map.values()

uses fgl;

m.IndexOfData(v) >= 0

m.value?(v)

Map.values(m) |> Enum.member?(v)

elem v (elems m)

in_array($v, $m, true);

Demo
Doc

Object.values (m).indexOf (v) !== -1

!m.values.find(_ == v).isEmpty()

using System.Collections.Generic;

_m.ContainsValue(_v)

#include <iostream>
#include <unordered_map>

int main()
{  
    // simple comparison demo
    std::unordered_map<int,char> example = {{1,'a'},{2,'b'}};

    size_t nElements = example.count(2);
    if (nElements) {
        std::cout << "Found " << nElements << " values." << '\n';
    } else {
        std::cout << "Not found\n";
    }
}

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