javascript - 如何在javascript中检索数组中相同值的数量？

Question

var array = ['box','box','line','time','box']

例如：盒子重复了几次

Answer 1

干得好：

    var array = ['box','box','line','time','box'],
    map = {},
    key;

array.forEach(function(item) {
    if (map[item] === undefined) {
        map[item] = 1;
    } else {
        map[item]++;
    }
});

for (key in map) {
    console.log(" key:", key, " repeated:", map[key]);
}