say I have an array with the following ten values: 329,374,353,336,137,340,374,374,356,329 I want to create a new array which uses those values and creates a sum according to their position, so that the new array (based on those values) would look like so:
329, 329+374, 329+374+353, 329+374+353+336, ... using javascript alone (no jquery) how can I achieve that?
You can use .map() and a running total variable:
var array = [329,374,353,336,137,340,374,374,356,329], sum = 0;
var result = array.map(function(item) {
sum += item;
return sum;
});
console.log(result);
Working demo: http://jsfiddle.net/jfriend00/9ekkk1r3/
var array = [329,374,353,336,137,340,374,374,356,329], sum = 0;
var result = array.map(function(item) {
sum += item;
return sum;
});
// show results in snippet
document.write("[" + result.join(',') + "]");.map() is useful here because it both iterates through the source array and creates a new result array which is exactly what you want to do. Then, all your have to do to simplify the result is to keep a running total of the sum so far so you know what to add for each new value.
input = [329,374,353,336,137,340,374,374,356,329]
output = [input[0]]
for (var i = 1; i < input.length; ++i){
output[i] = output[i-1]+input[i];
}
for loop over .map() which is built exactly for an iteration which creates a new array..map(), .forEach() and .reduce() as they can be very useful.