Finding the number of keys in an object [duplicate]

Question

Possible Duplicate:
How to efficiently count the number of keys/properties of an object in JavaScript?

var values = [{     'SPO2': 222.00000,     'VitalGroupID': 1152,     'Temperature': 36.6666666666667,     'DateTimeTaken': '/Date(1301494335000-0400)/',     'UserID': 1,     'Height': 182.88,     'UserName': null,     'BloodPressureDiastolic': 80,     'Weight': 100909.090909091,     'TemperatureMethod': 'Oral',     'Resprate': null,     'HeartRate': 111,     'BloodPressurePosition': 'Standing',     'VitalSite': 'Popliteal',     'VitalID': 1135,     'Laterality': 'Right',     'HeartRateRegularity': 'Regular',     'HeadCircumference': '',     'BloodPressureSystolic': 120,     'CuffSize': 'XL' }];  for (i=0; i < values.length; i++) {         alert(values.length) // gives me 2.  

How can find how many keys my object has?

Answer 1

var value = {     'SPO2': 222.00000,     'VitalGroupID': 1152,     'Temperature': 36.6666666666667,     'DateTimeTaken': '/Date(1301494335000-0400)/',     'UserID': 1,     'Height': 182.88,     'UserName': null,     'BloodPressureDiastolic': 80,     'Weight': 100909.090909091,     'TemperatureMethod': 'Oral',     'Resprate': null,     'HeartRate': 111,     'BloodPressurePosition': 'Standing',     'VitalSite': 'Popliteal',     'VitalID': 1135,     'Laterality': 'Right',     'HeartRateRegularity': 'Regular',     'HeadCircumference': '',     'BloodPressureSystolic': 120,     'CuffSize': 'XL' };  alert(Object.keys(value).length); 

Answer 2

try

Object.keys(values).length 

see: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/keys

for compatiblity

if(!Object.keys) Object.keys = function(o){  if (o !== Object(o))       throw new TypeError('Object.keys called on non-object');  var ret=[],p;  for(p in o) if(Object.prototype.hasOwnProperty.call(o,p)) ret.push(p);  return ret; } 

or use:

function numKeys(o){ var i=0; for(p in o) if(Object.prototype.hasOwnProperty.call(o,p)){ i++}; return i; }