如何在JavaScript数组计重复的值 [英] How to count duplicate value in an array in javascript

问题描述

目前，我得到了这样的一个数组：

  VAR uniqueCount =阵列（）;
 

在了几步，我的数组看起来像：

  uniqueCount = [A，B，C，D，D，E，A，B，C，F，G，H，H，H，E，A]。
 

我怎么能算一个，B，C究竟有多少数组中？我想有这样的结果：

  A = 3
B = 1
C = 2
D = 2
 

等。

解决方案

 函数count（）{
    array_elements = [一，B，C，D，E，一个，B，C，F，G，H，H ，H，E，一个];    array_elements.sort（）;    无功电流=无效;
    变种CNT = 0;
    对于（VAR I = 0; I＆LT; array_elements.length;我++）{
        如果（array_elements [I]！=电流）{
            如果（CNT大于0）{
                的document.write（电流+'来 - ＆GT;'+ CNT +'时代＆LT; BR＆GT;'）;
            }
            电流= array_elements [I];
            CNT = 1;
        }其他{
            CNT ++;
        }
    }
    如果（CNT大于0）{
        的document.write（电流+'来 - ＆GT;'+ CNT +'时代'）;
    }}
 

演示小提琴

Currently, I got an array like that:

var uniqueCount = Array();

After a few steps, my array looks like that:

uniqueCount = [a,b,c,d,d,e,a,b,c,f,g,h,h,h,e,a];

How can I count how many a,b,c are there in the array? I want to have a result like:

a = 3
b = 1
c = 2
d = 2

etc.

解决方案

function count() {
    array_elements = ["a", "b", "c", "d", "e", "a", "b", "c", "f", "g", "h", "h", "h", "e", "a"];

    array_elements.sort();

    var current = null;
    var cnt = 0;
    for (var i = 0; i < array_elements.length; i++) {
        if (array_elements[i] != current) {
            if (cnt > 0) {
                document.write(current + ' comes --> ' + cnt + ' times<br>');
            }
            current = array_elements[i];
            cnt = 1;
        } else {
            cnt++;
        }
    }
    if (cnt > 0) {
        document.write(current + ' comes --> ' + cnt + ' times');
    }

}

Demo Fiddle

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