How can I get the key value in a JSON object

Question

How do I get the key value in a JSON object and the length of the object using JavaScript  For example             quot amount quot    quot  12185 quot        quot job quot    quot GAPA quot        quot month quot    quot JANUARY quot        quot year quot    quot 2010 quot                quot amount quot    quot 147421 quot        quot job quot    quot GAPA quot        quot month quot    quot MAY quot        quot year quot    quot 2010 quot                quot amount quot    quot 2347 quot        quot job quot    quot GAPA quot        quot month quot    quot AUGUST quot        quot year quot    quot 2010 quot         Here  length of this array is 3  For getting  value is fine   0  amount   in index 0  it has three name value pairs  So  I need to get the name  like amount or job    totally four name  and also how do I count how many names there are

User · Answer

JSON content is basically represented as an associative array in JavaScript  You just need to loop over them to either read the key or the value      var JSON Obj      quot one quot  1   quot two quot  2   quot three quot  3   quot four quot  4   quot five quot  5            Read key     for  var key in JSON Obj           console log key          console log JSON Obj key

User · Answer

You may need   Object keys JSON 0      To get something like      amount    job    month    year        Note  Your JSON is invalid

User · Answer

You can simply traverse through the object and return if a match is found  Here is the code  returnKeyforValue   function         var JsonObj     quot one quot  1   quot two quot  2   quot three quot  3   quot four quot  4   quot five quot  5            for  key in JsonObj            if JsonObj key       quot Keyvalue quot                 return key

User · Answer

Try out this   var str      name     user     var jsonData   JSON parse str        console log jsonData name     Array Object  str       name     user      name     user2      jsonData   JSON parse str        console log jsonData 0  name

User · Answer

When you parse the JSON representation  it ll become a JavaScript array of objects   Because of this  you can use the  length property of the JavaScript array to see how many elements are contained  and use a for loop to enumerate it

User · Answer

First off  you re not dealing with a  JSON object   You re dealing with a JavaScript object  JSON is a textual notation  but if your example code works   0  amount   you ve already deserialized that notation into a JavaScript object graph   What you ve quoted isn t valid JSON at all  in JSON  the keys must be in double quotes  What you ve quoted is a JavaScript object literal  which is a superset of JSON       Here  length of this array is 2    No  it s 3      So  i need to get the name  like amount or job    totally four name  and also to count how many names are there    If you re using an environment that has full ECMAScript5 support  you can use Object keys  spec   MDN  to get the enumerable keys for one of the objects as an array  If not  or if you just want to loop through them rather than getting an array of them   you can use for  in   var entry  var name  entry   array 0   for  name in entry           here   name  will be  amount    job    month   then  year   in no defined order      Full working example    x000D   x000D   function     x000D     x000D    var array     x000D        x000D        amount  12185  x000D        job   GAPA   x000D        month   JANUARY   x000D        year   2010  x000D         x000D        x000D        amount  147421  x000D        job   GAPA   x000D        month   MAY   x000D        year   2010  x000D         x000D        x000D        amount  2347  x000D        job   GAPA   x000D        month   AUGUST   x000D        year   2010  x000D        x000D       x000D     x000D    var entry  x000D    var name  x000D    var count  x000D     x000D    entry   array 0   x000D     x000D    display  Keys for entry 0     x000D    count   0  x000D    for  name in entry    x000D      display name   x000D        count  x000D      x000D    display  Total enumerable keys      count   x000D   x000D           Basic utility functions x000D     x000D    function display msg    x000D      var p   document createElement  p    x000D      p innerHTML   msg  x000D      document body appendChild p   x000D      x000D     x000D        x000D   x000D   x000D    Since you re dealing with raw objects  the above for  in loop is fine  unless someone has committed the sin of mucking about with Object prototype  but let s assume not   But if the object you want the keys from may also inherit enumerable properties from its prototype  you can restrict the loop to only the object s own keys  and not the keys of its prototype  by adding a hasOwnProperty call in there   for  name in entry      if  entry hasOwnProperty name         display name         count

[javascript] How can I get the key value in a JSON object?

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