mapping an array of strings to an array of numbers based on key value pairs of another object-CodePudding

I am trying to map an array of strings

arrString = [
      ["A", "B"],
      ["C", "D"],
      ["E", "F"],
      ["D", "A"],
      ["F", "C"],
      ["G", "E"]
    ]

based on an object of key values:

map =  {
  '0': 'A',
  '1': 'B',
  '2': 'C',
  '3': 'D',
  '4': 'E',
  '5': 'F',
  '6': 'G'
}

into an array of numbers

arrNum = [
      ["0", "1"],
      ["2", "3"],
      ["4", "5"],
      ["3", "0"],
      ["5", "2"],
      ["6", "4"]
    ]

This is what I have done:

    const map = {}
    const arrNum = Array.from(new Array(arrString.length), () => new Array(arrString[0].length).fill([]));
    for(let i = 0; i < arr2.length; i  ){
        map[i] = arr2[i]
    }
    for(let ele in arrString){
    // I can't figure out how to if the obbject value is equal to ele push it's key to arrNum
        if (Object.values(map).includes(ele)) 
    }

As you can see I am trying to loop through arrString and then if any element equals a value in map I want to add its key to arrNum.

So anyone knows how to do it so I can end up with arrNum?

CodePudding user response：

First invert the map, then use it to match the letters.

const arrString = [
      ["A", "B"],
      ["C", "D"],
      ["E", "F"],
      ["D", "A"],
      ["F", "C"],
      ["G", "E"]
    ] 
    
const map =  {
  '0': 'A',
  '1': 'B',
  '2': 'C',
  '3': 'D',
  '4': 'E',
  '5': 'F',
  '6': 'G'
}

const invertedMap = Object.fromEntries(Object.entries(map).map(([a,b])=>[b,a]))

console.log('Inverted Map:',invertedMap)

const output = arrString.map(inner => inner.map(char => invertedMap[char]))

console.log('Result:',output)

CodePudding user response：

const arrString = [
    ["A", "B"],
    ["C", "D"],
    ["E", "F"],
    ["D", "A"],
    ["F", "C"],
    ["G", "E"]
]

map = {
    '0': 'A',
    '1': 'B',
    '2': 'C',
    '3': 'D',
    '4': 'E',
    '5': 'F',
    '6': 'G'
}

const arrNum = arrString.map(as => as.map(a => {
    for(const k in map){
        if (map[k] === a) return k;
    }
}));

console.log(arrNum);

CodePudding user response：

You can use:

const arrString = [
    ["A", "B"],
    ["C", "D"],
    ["E", "F"],
    ["D", "A"],
    ["F", "C"],
    ["G", "E"]
];

map =  {
  '0': 'A',
  '1': 'B',
  '2': 'C',
  '3': 'D',
  '4': 'E',
  '5': 'F',
  '6': 'G'
};

const keys = Object.keys(map);
const arrNum = arrString.map(item => item.map(value => keys.find(key => map[key] === value)));

console.log(arrNum);