Question

我有一个数组

data = [ '2016-12-12 pass [pass]',
  '2016-12-12 pass [pass]',
  '2016-12-12 fail [fail]',
  '2016-12-13 fail [fail]',
  '2016-12-14 fail [fail]',
  '2016-12-14 pass [pass]',
  '2016-12-14 pass [pass]',
  '2016-12-15 pass [pass]',
  '2016-12-16 fail [fail]' ]

我尝试了很多方法来完成使用各种功能，但无法找到如何实现这种格式：

2016-12-12 pass:2 fail: 1
2016-12-13 pass:0 fail: 1
2016-12-14 pass:2 fail: 1
2016-12-15 pass:1 fail: 0
2016-12-16 pass:0 fail: 1

Answer 1

以这种方式：

＆＃13;

const data = [
  '2016-12-12 pass [pass]',
  '2016-12-12 pass [pass]',
  '2016-12-12 fail [fail]',
  '2016-12-13 fail [fail]',
  '2016-12-14 fail [fail]',
  '2016-12-14 pass [pass]',
  '2016-12-14 pass [pass]',
  '2016-12-15 pass [pass]',
  '2016-12-16 fail [fail]',
];

const result = {};

data.forEach(item => {
  const [date, passFail] = item.split(' ');
  
  if (!(date in result)) {
    result[date] = { pass: 0, fail: 0 };
  }
  
  result[date][passFail] += 1;
});

console.log(result);

＆＃13;

正如您在输出中看到的，这将返回一个对象，其属性名称为日期，其值为具有属性pass和fail的对象。

请注意，您可以使用reduce而不是forEach来保存一行，但如果您要对该对象进行变更，那么reduce就毫无意义，所以我＆＃39 ;为了简单起见，使用了forEach。

另请注意，虽然在实践中（即在当前的JS引擎中）对象保留了它们的属性。插入顺序，严格来说JavaScript对象属性是无序的。如果你想对订单严格要求，那么你需要使用一个数组，在这种情况下，最简单的解决方案就是如下所述的事后转换：

＆＃13;

const result = {
  "2016-12-12": { pass: 2, fail: 1 },
  "2016-12-13": { pass: 0, fail: 1 },
  "2016-12-14": { pass: 2, fail: 1 },
  "2016-12-15": { pass: 1, fail: 0 },
  "2016-12-16": { pass: 0, fail: 1 },
};

const resultArray = Object.keys(result).sort()
                      .map(key => [ key, result[key] ]);

console.log(resultArray);

＆＃13;

Answer 2

您可以使用reduce()并返回对象数组。

var data = [ '2016-12-12 pass [pass]',
  '2016-12-12 pass [pass]',
  '2016-12-12 fail [fail]',
  '2016-12-13 fail [fail]',
  '2016-12-14 fail [fail]',
  '2016-12-14 pass [pass]',
  '2016-12-14 pass [pass]',
  '2016-12-15 pass [pass]',
  '2016-12-16 fail [fail]' ]
  
var result = Object.values(data.reduce(function(r, e) {
  var arr = e.split(' ')
  if(!r[arr[0]]) r[arr[0]] = {date: arr[0], pass: 0, fail: 0} 
  r[arr[0]][arr[1]]++
  return r;
}, {}))

console.log(JSON.stringify(result))

如果你不能使用Object.values()，你最后可以在对象上使用map。

var data = [ '2016-12-12 pass [pass]',
  '2016-12-12 pass [pass]',
  '2016-12-12 fail [fail]',
  '2016-12-13 fail [fail]',
  '2016-12-14 fail [fail]',
  '2016-12-14 pass [pass]',
  '2016-12-14 pass [pass]',
  '2016-12-15 pass [pass]',
  '2016-12-16 fail [fail]' ]
  
var result = data.reduce(function(r, e) {
  var arr = e.split(' ')
  if(!r[arr[0]]) r[arr[0]] = {date: arr[0], pass: 0, fail: 0} 
  r[arr[0]][arr[1]]++
  return r;
}, {})

result = Object.keys(result).map(e => result[e])

console.log(JSON.stringify(result))

Answer 3

您可以使用reduce将日期哈希到这样的对象中:(注意输出是对象的对象）

function group(arr) {
  return arr.reduce(function(hash, e) {      // for each element e in the array arr
    var parts = e.split(' ');                // split the element e by space
    if(hash[parts[0]]) {                     // if the date (part 0) is already hashed
      hash[parts[0]][parts[1]]++;            // then increment the equivalent pass or fail (part 1)
    }
    else {                                   // if not
      hash[parts[0]] = {pass: 0, fail: 0};   // create a new object for the date
      hash[parts[0]][parts[1]]++;            // increment its pass or fail value
    }
    return hash;
  }, {});
}

var array = ['2016-12-12 pass [pass]',
  '2016-12-12 pass [pass]',
  '2016-12-12 fail [fail]',
  '2016-12-13 fail [fail]',
  '2016-12-14 fail [fail]',
  '2016-12-14 pass [pass]',
  '2016-12-14 pass [pass]',
  '2016-12-15 pass [pass]',
  '2016-12-16 fail [fail]'
];

console.log(group(array));

从数组中提取组合结果

3 个答案: