CODEWITHSUNDEEP
javascript
chiradee
chiradee

Reputation: 105

Comaparing a variable inside a loop

I'm trying to compare for some duplicate value inside a loop because I need to do some logic. My problem is that I can't get the output that I expected. 

var tempVal;
for (i = 0; i < obj.length; i++) {
    var items = obj[i];
    tempVal = items.fund;
    console.log(tempVal); 
    console.log(tempVal == tempVal); 
    if(tempVal == tempVal){
        //do something
    }

In my example I have 2 same value in tempVal variable. My console.log(tempVal == tempVal) returns true in first loop but I thought it would return null or undefined in first loop because there's nothing to compare because it's empty on the first loop. What I need is top first return false then true. Thanks

Upvotes: 0

Views: 110

Answers (3)

Hamzeen Hameem
Hamzeen Hameem

Reputation: 2560

Looking at your code, I thought this is what you're trying to achieve:

var src = [
  {
    "index": 0,
    "fund": 100
  },
  {
    "index": 1,
    "fund": 200
  },
  {
    "index": 2,
    "fund": 100
  }];

var tempFunds = [];
const uniqueFunds = src.filter(item => {
  if (tempFunds.indexOf(item.fund) === -1) {
    tempFunds.push(item.fund);
    return item;
  }
});

// logs the array with unique funds
console.log(uniqueFunds);

You can implement an else branch above if you want to deal with duplicate fund(s). Although there is no issue with your choice to use a for loop, you could also consider map or filter function(s) based on your problem.

Upvotes: 0

Sachin Kumar
Sachin Kumar

Reputation: 3240

You haven't defined the initial value. So obuse a variable compare with them self are always equal. Why are you not using another name for remove complexity also. 

var tempVal;
    for (i = 0; i < obj.length; i++) {
       var items = obj[i];
       temp = items.fund;
       console.log(temp); 
       console.log(temp == tempVal); 
         if(temp == tempVal){
              //do something
                 }

Upvotes: 0

Sajeetharan
Sajeetharan

Reputation: 222722

You are comparing the same variable, obviously they are equal, create another variable and compare.

 tempVal = items.fund;
 console.log(tempVal); 
 console.log(tempVal == tempVal); //both are same

Upvotes: 2

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