I've got an array with dictionaries in it. Like this:

[{date:1991, value: 78}, {date:1992, value: 102}, {date:1993, value: 277}]

What's a good way to search for the object with date:1991 and return the value?

I've got an array with dictionaries in it. Like this:

[{date:1991, value: 78}, {date:1992, value: 102}, {date:1993, value: 277}]

What's a good way to search for the object with date:1991 and return the value?

• javascript
• arrays
• dictionary

• ues a for or while loop – Azad Commented Dec 15, 2016 at 9:04

5 Answers 5

Using filter() of method, you can do it as,

const dict = [ {date:1991, value: 78}, 
              {date:1992, value: 102}, 
              {date:1993, value: 277} ]

console.log(dict.filter(obj => obj.date === 1991))

You could also use a user defined function for doing the same as you requested, if you want answer in simple for and if loops.

var dict = [{date:1991, value: 78}, {date:1992, value: 102}, {date:1993, value: 277}]

function search_obj(dict, year) {
  for (obj of dict) {
    if (obj.date === year) {
      return obj
    }
  }
}

console.log(search_obj(dict, 1991))

create your own search function.

var arr = [{date:1991, value: 78}, {date:1992, value: 102}, {date:1993, value: 277}];

function searchFn(searchDate){

    for(var i = 0; i < arr.length; i++)
        if(arr[i] == searchDate)
            return arr[i];
}

//search
searchFn(1991);//{date:1991, value: 78}
searchFn(1992);//{date:1992, value: 102}

You can use Array#find method.

var data = [{
    date: 1991,
    value: 78
  }, {
    date: 1992,
    value: 102
  }, {
    date: 1993,
    value: 277
  }],
  date = 1991;

console.log(
  (data.find(function(v) {
    return v.date == date;
  }) || {}).value
)

For older browser check polyfill option of find method.

simply use forEach method .

var arr=[{date:1991, value: 78}, {date:1992, value: 102}, {date:1993, value: 277},{date:1991, value: 79}];
var v=1991,ans=[];

arr.forEach(function(a){
if(a.date==v)
   ans.push(a.value);
});
console.log(ans);

Use a simple filter statement:

var data = [{date:1991, value: 78}, {date:1992, value: 102}, {date:1993, value: 277}]
var result = data.filter(x => x.date == 1991)
console.log(result)