如何在Javascript / Jquery中使用json中的'Key'获取'Value'

Question

I have the following Json string. I want to get the 'Value' using 'Key', something like

giving 'BtchGotAdjust' returns 'Batch Got Adjusted';

var jsonstring=
[{"Key":"BtchGotAdjust","Value":"Batch Got Adjusted"},{"Key":"UnitToUnit","Value":"Unit To Unit"},]

Answer 1

Wow... Looks kind of tough! Seems like you need to manipulate it a bit. Instead of functions, we can create a new object this way:

var jsonstring =
    [{"Key":"BtchGotAdjust","Value":"Batch Got Adjusted"},{"Key":"UnitToUnit","Value":"Unit To Unit"},];
     var finalJSON = {};
     for (var i in jsonstring)
         finalJSON[jsonstring[i]["Key"]] = jsonstring[i]["Value"];

You can use it using:

finalJSON["BtchGotAdjust"]; // Batch Got Adjusted

Answer 2

As you have an array in your variable, you have to loop over the array and compare against the Key -Property of each element, something along the lines of this:

for (var i = 0; i < jsonstring.length; i++) {
  if (jsonstring[i].Key === 'BtchGotAdjust') {
    console.log(jsonstring[i].Value);
  }
}

By the way, I think your variable name jsonstring is a little misleading. It does not contain a string. It contains an array. Still, the above code should give you a hint in the right direction.

Answer 3

Personally I would create a map from the array and then it acts like a dictionary giving you instantaneous access. You also only have to iterate through the array once to get all the data you need:

var objectArray = [{"Key":"BtchGotAdjust","Value":"Batch Got Adjusted"},{"Key":"UnitToUnit","Value":"Unit To Unit"}]

var map = {}

for (var i=0; i < objectArray.length; i++){
    map[objectArray[i].Key] = objectArray[i]
}

console.log(map);
alert(map["BtchGotAdjust"].Value)
alert(map["UnitToUnit"].Value)

See js fiddle here: http://jsfiddle.net/t2vrn1pq/1/