hope I can get some help here.
I have a javascript array that looks like so:
var stages = ['Stage 1', 'Stage 1', 'Stage 2', 'Stage 3', 'Stage 1'];
var stageValues = [10, 20, 10, 30, 50];
What I would like to achieve is to take the above data and have it transformed into something like this:
Stage 1: 10, 20, 50
Stage 2: 10
Stage 3: 30
Kind of a bit stumped on how to do this... Any ideas would be appreciated.
Thank you.
Here is a possible solution. The function returns an object key/value where each key is an element of the first array and the value is an array made of corresponding elements of the second array.
function joint_arrays(arr1,arr2) {
toR = {};
if (arr1.length===arr2.length){
for (var i=0;i<arr1.length;i++) {
if (arr1[i] in toR) {
toR[arr1[i]].push(arr2[i]);
}
else {
toR[arr1[i]] = [arr2[i]];
}
}
}
return toR;
}
For example:
var res= joint_arrays(stages,stageValues);
console.log(res);
returns
[object Object] {
Stage 1: [10, 20, 50],
Stage 2: [10],
Stage 3: [30]
}
You could iterate over two arrays and group it. But much more easier will be the functional approach with some library like underscore or lodash
var stages = ['Stage 1', 'Stage 1', 'Stage 2', 'Stage 3', 'Stage 1'];
var stageValues = [10, 20, 10, 30, 50];
var grouped = _.groupBy(stageValues, function (elem, index) {
return stages[index];
});
A solution with Array.prototype.reduce:
var stages = ['Stage 1', 'Stage 1', 'Stage 2', 'Stage 3', 'Stage 1'],
stageValues = [10, 20, 10, 30, 50],
obj = stages.reduce(function (r, a, i) {
r[a] = r[a] || [];
i in stageValues && r[a].push(stageValues[i]);
return r;
}, {});
document.write('<pre>' + JSON.stringify(obj, 0, 4) + '</pre>');