如何比较输出的过去值

Question

有人知道如何比较下面的图像吗，我很难解决这个问题。 :)非常感谢:)

输出位于 for 循环内。我只想比较和计数。

下面的示例代码。

var array_date = ["2018/03/07","2018/03/07","2018/03/07","2018/03/07","2018/03/07","2018/03/08","2018/03/09","2018/03/09"];
var eventType = ["Absent","Absent","Late","Late","Late","Absent","Absent","Late"];
var prev_array_date="";
var prev_eventType="";
for(i = 0; i <array_date.length; i++){
console.log("sort_unique_arr_date[b]: "+array_date[i]);
console.log("temp_eventType: "+eventType[i]);
console.log("---------------------------------------------------------")
if(prev_array_date == "" && prev_eventType == ""){
prev_array_date = array_date[i];
prev_eventType = eventType[i];
}else{
  if(prev_array_date == array_date[i] && prev_eventType == eventType[i]){
  
  }
  else{
  
  }
}
}

我只想要这样的输出：

Output:
2018/03/07
Absent - 2
2018/03/07
Late - 3
2018/03/08
Absent - 1
2018/03/09
Absent - 1
2018/03/09
Late - 1

控制台映像

Answer 1

您可以使用日期和类型作为对象的索引，并根据需要轻松填充它。尝试使用以下代码，它应该做你想要的

var array_date = ["2018/03/07","2018/03/07","2018/03/07","2018/03/07","2018/03/07","2018/03/08","2018/03/09","2018/03/09"];
var eventType = ["Absent","Absent","Late","Late","Late","Absent","Absent","Late"];
var count_obj = {};
for(i = 0; i <array_date.length; i++){
  console.log("sort_unique_arr_date[b]: "+array_date[i]);
  console.log("temp_eventType: "+eventType[i]);
  console.log("---------------------------------------------------");
  let key = array_date[i];
  let s_key = eventType[i];
  if( ! count_obj.hasOwnProperty(key) ){
        count_obj[ key ] = {};
  }
  if( ! count_obj[ key ].hasOwnProperty(s_key) ){
        count_obj[ key ][ s_key ] = 0;
  }
    count_obj[ key ][ s_key ] += 1;
}
console.log("--OUTPUT BELOW--");
for( date in count_obj){
    console.log(date);
    for( type in count_obj[date] ){
        // if you put 'console.log(date);' here you'll have exactly the output you wanted
        console.log(type +' - '+count_obj[date][type]);
    }
}

检查小提琴