Question

我有一个如下的多数组

[
    {Name: "test1", Role: "Role1", Product: "Product4", Rate: 146, Rate_Override: 0},
    {Name: "test2", Role: "Role1", Product: "Product1", Rate: 147, Rate_Override: 0},
    {Name: "test3", Role: "Role1", Product: "Product1", Rate: 148, Rate_Override: 0},
    {Name: "test4", Role: "Role2", Product: "Product1", Rate: 149, Rate_Override: 0},
    {Name: "test5", Role: "Role3", Product: "Product2", Rate: 146, Rate_Override: 0},
    {Name: "test6", Role: "Role1", Product: "Product1", Rate: 146, Rate_Override: 0},
]

如何获取与角色和产品匹配的重复记录数？

Role1 and Product4 is 1

的组合

Role1 and Product1 is 3

的组合

Role2 and Product1 is 1

的组合

Role3 and Product2 is 1

的组合

Answer 1

请尝试

const a = [
    {Name: "test1", Role: "Role1", Product: "Product4",Rate: 146,Rate_Override: 0},
    {Name: "test2", Role: "Role1", Product: "Product1",Rate: 147,Rate_Override: 0},
    {Name: "test3", Role: "Role1", Product: "Product1",Rate: 148,Rate_Override: 0},
    {Name: "test4", Role: "Role2", Product: "Product1",Rate: 149,Rate_Override: 0},
    {Name: "test5", Role: "Role3", Product: "Product2",Rate: 146,Rate_Override: 0},
    {Name: "test6", Role: "Role1", Product: "Product1",Rate: 146,Rate_Override: 0}
]


const match = (role, product) => a.reduce((res, o) => res + (o.Role == role && o.Product == product), 0);

console.log(match('Role1', 'Product4')); // 1
console.log(match('Role1', 'Product1')); // 3
console.log(match('Role2', 'Product1')); // 1
console.log(match('Role3', 'Product2')); // 1

Answer 2

您可以使用Map并计算所需的组合属性。

var array = [{ Name: "test1", Role: "Role1", Product: "Product4",Rate: 146,Rate_Override: 0 }, { Name: "test2", Role: "Role1", Product: "Product1",Rate: 147,Rate_Override: 0 }, { Name: "test3", Role: "Role1", Product: "Product1",Rate: 148,Rate_Override: 0 }, { Name: "test4", Role: "Role2", Product: "Product1",Rate: 149,Rate_Override: 0 }, { Name: "test5", Role: "Role3", Product: "Product2",Rate: 146,Rate_Override: 0 }, { Name: "test6", Role: "Role1", Product: "Product1",Rate: 146,Rate_Override: 0 }],
    keys = ['Role', 'Product'],
    count = Array.from(
        array.reduce(
            (m, o) =>
                (k => m.set(k, (m.get(k) || 0) + 1))
                (keys.map(k => o[k]).join('|')),
            new Map
        ),
        ([k, v]) => k.split('|').concat(v)
    );

console.log(count);

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如何识别多数组中重复元素的数量

2 个答案: