如何有效匹配多个值

Question

I am trying to come up with a matching algorithm that matches on 3 attributes and I can't think of an effective solution. Here is the psuedocode for my algorithm

The algorithm does the following:

• Check if there is a match on the first criteria.
• If there is match on first criteria then I try to narrow the match down based on the other 2 criterias.
• If there is no match on the first criteria, then try to make a match on the second criteria.
• If there is a match on the second criteria, then I try to narrow the match down based on the last criteria.
• Etc...

It seems like this algorithm just repeats itself, and if I add another value to match on, then this algorithm grows very large real quickly.

//try to match on criteria 1
if results exist for match on criteria 1 {
    //try to match on criteria 1 & 2
    if results exist for match on criteria 1 & 2 {
        //try to match on criteria 3
        if result exist for match on criteria 1,2,3 {
            return results for match on 1,2,3
        }
        else
            return results for match on 1,2
    }
    else
        return results for match on 1
}
//try to match on criteria 2
else if results exist for match on criteria 2 {
    //try to match on criteria 2 & 3
    if result exist for match on criteria 2,3 {
        return results for match on 2,3
    }
    else
        return results for match on 2
}
//try to match on criteria 3
else if results exist for match on criteria 3 {
    return results for match on 3
}
else {
    no match
}

Is there any better way to do this? It seems like

Answer 1

Here is an implementation in Javascript if I understand you correctly.

function filter(arr, condition) {
  var retval = [];
  for (i in arr) if (condition(arr[i])) retval.push(arr[i]);
  return retval;
}

function first_match(arr, conditions) {
  if (conditions.length == 0) return("No match");
  var initial_arr = Array.prototype.slice.call(arr);
  var prev_arr;
  var i = 0;
  for (; i < conditions.length && arr.length != 0; i++) {
    prev_arr = Array.prototype.slice.call(arr);
    arr = filter(arr, conditions[i]);
  }
  if (i <= 1 && arr.length == 0) return first_match(initial_arr, Array.prototype.slice.call(conditions, 1));
  else if (i == conditions.length && arr.length != 0) return arr;
  else return prev_arr;
}

Examples

var conditions = [function(x) { return x > 3; },
                  function(x) { return x % 2 == 0; },
                  function(x) { return Math.sqrt(x) % 1 == 0; }];

var example1 = [1,2,3,4,5,6,7,8,9,10];
console.log(first_match(example1, conditions)); // [4] - all three hold
var example2 = [1,2,3,5,6,7,8,9,10];
console.log(first_match(example2, conditions)); // [6, 8, 10] - First two hold
var example3 = [5, 7, 9];
console.log(first_match(example3, conditions)); // [5, 7, 9] - First one holds
var example4 = [-2, 0, 2];
console.log(first_match(example4, conditions)); // [0] - 2 & 3 hold
var example5 = [-2, 2];
console.log(first_match(example5, conditions)); // [-2, 2] - Only 2 holds
var example6 = [1];
console.log(first_match(example6, conditions)); // [1] - Last one holds
var example7 = [-1];
console.log(first_match(example7, conditions)); // "No match" - None hold