get index of all objects in a json array

Question

Here's my json::

[{ "name": "Roy", "city": "Dallas", "state": "Texas" }, { "name": "Karla", "city": "LA", "state": "California" },{ "name": "Felix", "city": "Las Vegas", "state": "Nevada" },{ "name": "Fred", "city": "Miami", "state": "Florida" },{ "name": "Bill", "city": "Atlanta", "state": "Georgia" },{ "name": "Mike", "city": "Chicago", "state": "Illinois" },{ "name": "Tim", "city": "Worcester", "state": "MA" },{ "name": "Ryan", "city": "Austin", "state": "Texas" },{ "name": "Sam", "city": "Boston", "state": "MA" },{ "name": "Sarah", "city": "Houston", "state": "Texas" }]

I want to capture all index numbers with state of Texas:

Please help.

Can you specify what you're struggling with? JSON parsing? Loop logic? A combination of the two? — Chuck Quinn IV
– Chuck Quinn IV, Commented Aug 25, 2017 at 18:29

Nina Scholz · Accepted Answer · 2017-08-25 18:34:38Z

1

You could use Array#reduce while collecting indices of matching state.

var array = [{ name: "Roy", city: "Dallas", state: "Texas" }, { name: "Karla", city: "LA", state: "California" }, { name: "Felix", city: "Las Vegas", state: "Nevada" }, { name: "Fred", city: "Miami", state: "Florida" }, { name: "Bill", city: "Atlanta", state: "Georgia" }, { name: "Mike", city: "Chicago", state: "Illinois" }, { name: "Tim", city: "Worcester", state: "MA" }, { name: "Ryan", city: "Austin", state: "Texas" }, { name: "Sam", city: "Boston", state: "MA" }, { name: "Sarah", city: "Houston", state: "Texas" }],
    indices = array.reduce((r, o, i) => (o.state === 'Texas' && r.push(i), r), []);

console.log(indices);

answered Aug 25, 2017 at 18:34

Nina Scholz

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Comments

Ibrahim Khan · Accepted Answer · 2017-08-25 18:32:32Z

You can use map() and filter() methods like following.

var data = [{ "name": "Roy", "city": "Dallas", "state": "Texas" }, { "name": "Karla", "city": "LA", "state": "California" },{ "name": "Felix", "city": "Las Vegas", "state": "Nevada" },{ "name": "Fred", "city": "Miami", "state": "Florida" },{ "name": "Bill", "city": "Atlanta", "state": "Georgia" },{ "name": "Mike", "city": "Chicago", "state": "Illinois" },{ "name": "Tim", "city": "Worcester", "state": "MA" },{ "name": "Ryan", "city": "Austin", "state": "Texas" },{ "name": "Sam", "city": "Boston", "state": "MA" },{ "name": "Sarah", "city": "Houston", "state": "Texas" }];

var indexes = data.map(function(item, i){
    if(item.state == "Texas") return i;
}).filter(function(item){ return item!=undefined; });

console.log(indexes);

Ashish Arora · Accepted Answer · 2017-08-25 18:33:08Z

0

You can enumerate the collection and add the indexes in an array, where state is 'Texas'. If you are using server side code, you can Deserialize the response (to a target type that contains same attributes as JSON object) using JSON parser. If you are using Javascript, you can JSON.parse(jsonString) to convert into an object array and then enumerate

answered Aug 25, 2017 at 18:33

Ashish Arora

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Comments

neh11 · Accepted Answer · 2017-08-25 18:48:56Z

0

You can use a for loop to achieve this. Iterating over a variable, say 'i', would be useful.

texas_indecies = [];
for (var i = 0; i < array.length; i++){
  if (array[i].state == "Texas"){
    texas_indecies.push(i);
  }
}

edited Aug 25, 2017 at 18:48

answered Aug 25, 2017 at 18:33

neh11

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Comments

Gabriel Alejandro · Accepted Answer · 2017-08-25 18:58:35Z

0

is this what you need?

var obj=[{ "name": "Roy", "city": "Dallas", "state": "Texas" }, { "name": "Karla", "city": "LA", "state": "California" },{ "name": "Felix", "city": "Las Vegas", "state": "Nevada" },{ "name": "Fred", "city": "Miami", "state": "Florida" },{ "name": "Bill", "city": "Atlanta", "state": "Georgia" },{ "name": "Mike", "city": "Chicago", "state": "Illinois" },{ "name": "Tim", "city": "Worcester", "state": "MA" },{ "name": "Ryan", "city": "Austin", "state": "Texas" },{ "name": "Sam", "city": "Boston", "state": "MA" },{ "name": "Sarah", "city": "Houston", "state": "Texas" }],
indexes=[];

for(var index in obj){
  if(obj[index]['state']=='Texas')
    indexes.push(index);
}

console.log(indexes);

edited Aug 25, 2017 at 18:58

answered Aug 25, 2017 at 18:32

Gabriel Alejandro

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