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i have the following loop which is iterating through an array and i try to access the next position of the current position in the array.

for( var i in myArray){
   var temp = myArray[i+1];
}

The problem is that it not add the 1 with the var i but it just appends the number 1 on the i. Like i is 2 and i do this 

i+1

the result is

21

and not 3.

Why is this so and how can i add the two variables?

Pero
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2 Answers2

7

Basically you are iterating over the keys of an object (an array is an object) and the keys are always strings (or symbol type in ES6). For converting to a number, you could just add an unary plus in front of it for converting a stringed number to a number.

var temp = myArray[+i + 1];

You might use better the classical iteration with a counter, like

var i, temp;
for (i = 0; i < array.length; i++) {
    temp = array[i + 1];
    // some more code
}

because for ... in iterates over all enumerable properties of the object, if exist. For more information read Why is using “for…in” with array iteration a bad idea?

Nina Scholz
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1

Parseint should be used to add two varibles

var test1= parseInt(10);
var test2= parseInt(20);

alert(test1+test2); // should now alert 30

This is how you can add two variables in Javascript....

Moiz Shafqat Husain
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