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Accepted
Stevn
Asked: 2020-08-24 07:32:42 +0800 CST 2020-08-24 07:32:42 +0800 CST

loop through json data with javascript

  • 772

I am trying to obtain the data from a json but not when searching for a data it throws me the error.

Uncaught TypeError: Cannot read property 'day' of undefined

$.ajax({
  url: url,
  //dataType: 'json',
  type: 'POST',
  jsonpCallback: "myJSON",
  success: function (json) {
    alert(json);
    var subjson = json.substring(7, json.length-1);
    alert(subjson);
    var jsonValido = JSON.stringify(eval("(" + subjson + ")"));
    var jsonFinal = JSON.parse(JSONize(jsonValido));
    alert(jsonFinal);
    //$("#resultado").html(json);
    alert("obtencion de datos: Dia" + jsonFinal[0]['dia'] + " A: " + jsonFinal[0]['A']);
    $("#resultado").html(jsonFinal[0]);
  }

I have reviewed how to obtain data and I saw that this is the way jsonFinal[0]['dia'], but I have not been able to access them.

the json to which I am querying the data has this format

{'dia':'01-08-2016','A':'3','B':'5','C':'33','D':'34','E':'3'},{'dia':'02-08-2016','A':'3','B':'3','C':'38','D':'30','E':'3'}
javascript

3 Answers

  1. Best Answer

    The format you put is wrong

    {'dia':'01-08-2016','A':'3','B':'5','C':'33','D':'34','E':'3'},{'dia':'02-08-2016','A':'3','B':'3','C':'38','D':'30','E':'3'}

    For it to be an array of objects it has to be enclosed in square brackets.

    [{'dia':'01-08-2016','A':'3','B':'5','C':'33','D':'34','E':'3'},{'dia':'02-08-2016','A':'3','B':'3','C':'38','D':'30','E':'3'}]

    Objects in JSON are enclosed in curly braces { } and within the curly braces are the properties of the objects with their respective values ​​(in quotes) separated by : (colon)

    { propiedad:"valor" }

    Multiple properties are separated by commas

    { propiedad:"valor", otro:"su valor" }

    To be able to group several objects they have to be put between brackets (like an array) and separate each object with a comma

    [ {propiedad:"valor"} , {otra:"valor"} ]

    A good short tutorial here

    • 3

  2. Use jsonFinal[0]['dia']when you have an array of objects.

    From the information you've put in the comments, you have a single object, not an array, so the way to access the property should be:

    jsonFinal['dia']

    either

    jsonFinal.dia
    • 2

  3. If you have an array like this:

    [{'dia':'01-08-2016','A':'3','B':'5','C':'33','D':'34','E':'3'},{'dia':'02-08-2016','A':'3','B':'3','C':'38','D':'30','E':'3'}]

    You can access the element you wanted this way

    //jsonFinal es el objeto devuelto por la solicitud del ajax que anteriormente mencionabas
var dia = jsonFinal[0].dia;

    If you want to access any other property you just have to call it after the point var A = jsonFinal[0].A; //or .B or whatever you have

    • 1