자바스크립트 unique_count_by_value()

1 개요[ | ]

자바스크립트 unique_count_by_value()

let revisions = [
    {user:'A', timestamp:'2018-01-15T10:55:04Z'},
    {user:'B', timestamp:'2017-07-14T17:08:00Z'},
    {user:'C', timestamp:'2016-12-27T05:48:18Z'},
    {user:'B', timestamp:'2016-03-29T05:00:16Z'},
    {user:'A', timestamp:'2015-09-28T08:06:25Z'}
];
function unique_count_by_value(rows, column) {
    const counts = [];
    for( const i in rows ) {
        if(counts.hasOwnProperty(rows[i][column])) counts[rows[i][column]]++;
        else counts[rows[i][column]] = 1;
    }
    return counts;
}
console.log( unique_count_by_value(revisions, 'user') );
// [ A: 2, B: 2, C: 1 ]
console.log( unique_count_by_value(revisions, 'asdf') );
// [ undefined: 5 ]

let rows = [
    { kind: "watermelon", price: 100 },
    { kind: "apple"     , price: 200 },
    { kind: "watermelon", price: 300 },
    { kind: "watermelon", price: 400 },
    { kind: "banana"    , price: 500 },
    { kind: "apple"     , price: 600 }
];
function unique_count_by_value(rows, column) {
    const counts = [];
    for( const i in rows ) {
        if(counts.hasOwnProperty(rows[i][column])) counts[rows[i][column]]++;
        else counts[rows[i][column]] = 1;
    }
    return counts;
}
console.log( unique_count_by_value(rows, 'kind') );
// [ watermelon: 3, apple: 2, banana: 1 ]
console.log( unique_count_by_value(rows, 'asdf') );
// [ undefined: 6 ]

2 같이 보기[ | ]