To also handle floating point numbers:
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(Older) JavaScript:
var arr = ["20.0","40.1","80.2","400.3"], n = arr.length, sum = 0; while(n--) sum += parseFloat(arr[n]) || 0; -
ECMA 5.1/6:
var arr = ["20.0","40.1","80.2","400.3"], sum = 0; arr.forEach(function(num){sum+=parseFloat(num) || 0;}); -
ES6:
var sum = ["20.0","40.1","80.2","400.3"].reduce((pv,cv)=>{ return pv + (parseFloat(cv)||0); },0);
The reduce() is available in older ECMAScript versions, the arrow function is what makes this ES6-specific.
I’m passing in 0 as the first
pvvalue, so I don’t need parseFloat around it — it’ll always hold the previous sum, which will always be numeric. Because the current value,cv, can be non-numeric (NaN), we use||0on it to skip that value in the array. This is terrific if you want to break up a sentence and get the sum of the numbers in it. Here’s a more detailed example:let num_of_fruits = ` This is a sentence where 1.25 values are oranges and 2.5 values are apples. How many fruits are there? `.split(/\s/g).reduce((p,c)=>p+(parseFloat(c)||0), 0); // num_of_fruits == 3.75
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jQuery:
var arr = ["20.0","40.1","80.2","400.3"], sum = 0; $.each(arr,function(){sum+=parseFloat(this) || 0;});
What the above gets you:
- ability to input any kind of value into the array; number or numeric string(
123or"123"), floating point string or number ("123.4"or123.4), or even text (abc) - only adds the valid numbers and/or numeric strings, neglecting any bare text (eg [1,’a’,’2′] sums to 3)