CODEWITHSUNDEEP
javascript
aman
aman

Reputation: 6252

Javascript not equal and OR

This looks a simple code but not sure what I am doing wrong here.

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

 var myJson = JSON.parse(data);
 for (var key in myJson) {
   var item = {
   Id: myJson[key].Id,
   Name: myJson[key].Name
 };

 if(item.Id != "01" || item.Id !="02")
 {
   alert(item.Id);   
 }
}

I am expecting to just show an alert as "03" but it shows 3 alert each for "01", "02" & "03"

Looks like != and OR operator not working ?

Upvotes: 2

Views: 1711

Answers (3)

Mamun
Mamun

Reputation: 68943

The || operator only returns false when both of its operands are false (and true in all other cases).

The && operator only returns true when both of its operands are true (and false in all other cases).

You have to use && instead of || in the if condition to get the expected result:

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

 var myJson = JSON.parse(data);
 for (var key in myJson) {
   var item = {
   Id: myJson[key].Id,
   Name: myJson[key].Name
 };

 if(item.Id != "01" && item.Id !="02")
 {
   alert(item.Id);   
 }
}

Upvotes: 8

Takit Isy
Takit Isy

Reputation: 10081

item.Id != "01" || item.Id !="02" will always be true, as it can't be equal to both of the values at the same time.

You only need to use && instead of ||:

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

 var myJson = JSON.parse(data);
 for (var key in myJson) {
   var item = {
   Id: myJson[key].Id,
   Name: myJson[key].Name
 };

 if(item.Id != "01" && item.Id !="02")
 {
   console.log(item.Id); // I prefer consoling, that's less agressive!
 }
}

⋅ ⋅ ⋅

If you also plan to do if(item.Id != "01" && item.Id !="02" && item.Id !="03"), you must want to use a > comparator and unary + on your string:

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

 var myJson = JSON.parse(data);
 for (var key in myJson) {
   var item = {
   Id: myJson[key].Id,
   Name: myJson[key].Name
 };

 if(+item.Id > 2)
 {
   console.log(item.Id); // I prefer consoling, that's less agressive!
 }
}

Hope it helps.

Upvotes: 1

Ele
Ele

Reputation: 33726

Actually is working as expected because the OR operator is returning true for cases when Id == 01 and Id == 02

What you want to do is to join the two operands with AND operator && and this way execute the logic just when Id != 01 AND Id != 02.

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

var myJson = JSON.parse(data);
for (var key in myJson) {
  var item = {
    Id: myJson[key].Id,
    Name: myJson[key].Name
  };

  if (item.Id != "01" && item.Id != "02") {
    alert(item.Id);
  }
}

Upvotes: 1

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