在JavaScript中寻找多维数组中的匹配项

Question

I am trying to match entire arrays in Javascript. I have a userInput array and I need to find a matching array within a multi-dimensional array and output the match.

var t1 = [0,0,0];
var t2 = [1,0,0];
var t3 = [0,0,1];
var userInput = [0,0,0];
var configs = [t1, t2, t3];

I am trying to find a way to match userInput to one of the other arrays and output the matching array. With underscore.js I can find a match one at a time without looping, but that returns a bool.

var result = _.isEqual(userInput,t1) returns true

I need to find the matching array inside the configs array. I can nest loops to go through configs, but I can't figure out how to match it to userInput.

Answer 1

You can use Array#findIndex to find the index of the matching config in the array. Use Array#every to find the config that is equal.

 var t1 = [0,0,0]; var t2 = [1,0,0]; var t3 = [0,0,1]; var userInput = [0,0,1]; // this will fit t3 (index 2) var configs = [t1, t2, t3]; var result = configs.findIndex(function(arr) { return arr.every(function(value, i) { return value === userInput[i]; }); }); console.log(result); 

Answer 2

Given input you can use Array.prototype.find() , Array.prototype.toString() or Array.prototype.join()

 var t1 = [0,0,0]; var t2 = [1,0,0]; var t3 = [0,0,1]; var userInput = [0,0,0]; var configs = [t1, t2, t3]; var result = configs.find(arr => arr.join() === userInput.join()); console.log(result); 

Answer 3

You can use a combination of some and every

 var t1 = [0,0,0]; var t2 = [1,0,0]; var t3 = [0,0,1]; var userInput = [0,0,0]; var configs = [t1, t2, t3]; var inputPresent = configs.some(a => userInput.every((u,i) => a[i] == u)); console.log(inputPresent); 

If you wanted to know the index of the existing input, you could just include a ternary

 var t1 = [0,0,0]; var t2 = [1,0,0]; var t3 = [0,0,1]; var userInput = [0,0,0]; var configs = [t1, t2, t3]; var inputIndex = -1; configs.some((a,n) => userInput.every((u,i) => a[i] == u)?(inputIndex=n,true):false); console.log(inputIndex); 

Answer 4

Would this work?

var result = _.find(configs, function(t) {
  return _.isEqual(userInput, t);
});

If you need to know the index:

var index = -1;
_.some(configs, function(t, idx) {
  if (_.isEqual(userInput, t)) {
    index = idx;
    return true;
  }
});
// index = -1 if not found, else the first index of configs that matches the userInput

Answer 5

I would be concerned about the place where there might be duplicates. If you can make a function that can test equality reliably then this is just a filter.

var matches = configs.filter(config => _.isEqual(config, userInput));
var match = matches[0];

If you wanted to invest into using a library more you could use something like find

var match = _.find(configs, config => _.isEqual(config, userInput));