I must be missing the proper term or else I'm sure I could find the answer by searching... in any case, here's what I want to do.
Through javascript, I get four variables (A, B, C, and D) that I would like to sort, and still keep track of the variable name (since it's encoded with meaning information).
Sample Data:
A = 2;
B = 1;
C = 4;
D = 3;
What I need to do now is sort them in value order (4,3,2,1) such that I can actually know the variable name ordering (C,D,A,B).
You can keep an array of value pair objects and then simply sort that array. Of course, the array's sort method need to know how to interpret the object but that can be done by supplying a comparison function to the sort method.
First declare your array of objects:
sample_data = [
{ name: 'A', value: 2 },
{ name: 'B', value: 1 },
{ name: 'C', value: 4 },
{ name: 'D', value: 3 }
];
Then write a comparison function:
function custom_compare (a,b) {
// I'm assuming all values are numbers
return a.value - b.value;
}
Then simply sort and reverse:
sample_data.sort(custom_compare).reverse();
To print out the sorted names simply iterate through the array:
for (var i=0;i<sample_data.length;i++) {
console.log(sample_data[i].name);
}
return b.value - a.value;. Also note that sort destructively sorts the array, so after the sort has run the sample_data-array is sorted. A common way to get around that is to copy the array before sorting it: sorted_data = sample_data.slice(0).sort(custom_compare);sample_data.slice(0).sort(function(a,b){return b.value - a.value;}).forEach(function(a){console.log(a.name, a.value);});
a.value - b.value use b.value - a.value.reverse_sort however, it would be fine. As is, the code above is self documenting with only a minimal hit in efficiency (reverse is O(n) after all).I think what you should be looking for something like "Associative arrays" implemented in Javascript.
