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javascript sorting strings starting with a number not working

I am trying to sort an object of strings, which would work with the normal sort function, but I am not able to get it working as the strings start with a number:

e.g.:

{ value: "10 items", value: "5 items", value: "100 items", value: "20 items" }

I want to make it ascending, so it becomes:

5 items
10 items
20 items
100 items

I’ve been trying to use:

data.sort((a, b) => a > b ? 1 : -1).map((a) => { return a;}

But that still shows it as:

10 items
100 items
20 items
5 items

Tags:

4

Answers


  1. 0

    You need to compare the first parts of your strings numerically, so we split them, get the first element, convert them to int and then we can compare it. See below:

    let data = [ "10 items", "5 items", "100 items", "20 items" ];
data.sort((a, b) => {
    let x = parseInt(a.split(" ")[0]);
    let y = parseInt(b.split(" ")[0]);
    if (x === y) {
        return 0;
    } else {
        return x > y ? 1 : -1;
    }
});
console.log(data);

    Note that I have reinterpreted your input, since the one you have given was obviously wrong, as repeating the same key inside an object (value) in this case is invalid.

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  2. 0

    You can extract the numbers with s.slice(0, s.indexOf(' ') and compare them:

    let data = [ "10 items", "5 items", "100 items", "20 items" ];
const getNum = s => s.slice(0, s.indexOf(' '));
data.sort((a, b) => (a = getNum(a), b = getNum(b), a-b));
console.log(data);

    If you want to speed up you could compare lengths of the numbers first and then compare them char-by-char if the length is equal:

    ` Chrome/124
-----------------------------------------------------
Alexander      ■ 1.00x | x1000000 174 183 189 192 197
Lajos Arpad      1.57x | x1000000 274 286 296 300 306
Peter Seliger  103.45x |   x10000 180 184 191 204 204
-----------------------------------------------------
https://github.com/silentmantra/benchmark `

    let data = [ "10 items", "5 items", "100 items", "20 items" ];

// @benchmark Alexander
data.toSorted((a, b) => {
  a = a.slice(0, a.indexOf(' ')), b = b.slice(0, b.indexOf(' '));
  if(a.length > b.length) return 1;
  if(a.length < b.length) return -1;
  for(let i = 0;i < a.length;i++){
    if(a[i] > b[i]) return 1;
    if(a[i] < b[i]) return -1;
  }
  return 0;
});

// @benchmark Peter Seliger
data.toSorted((a, b) => a.localeCompare(b, undefined, { numeric: true }));

// @benchmark Lajos Arpad
data.toSorted((a, b) => {
    let x = parseInt(a.split(" ")[0]);
    let y = parseInt(b.split(" ")[0]);
    if (x === y) {
        return 0;
    } else {
        return x > y ? 1 : -1;
    }
});

/*@skip*/ fetch('https://cdn.jsdelivr.net/gh/silentmantra/benchmark/loader.js').then(r => r.text().then(eval));
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  3. 0

    As @somethinghere mentioned in the comment you can use localeCompare to sort numerical data

    const data = [{ value: "10 items" },
              { value: "5 items"},
              {value: "100 items"},
              {value: "20 items"}
    ];
const result = data.sort((a, b) => a.value.localeCompare(b.value,undefined,{numeric:true}));
console.log(result );
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  4. 0 
    console.log(
  Object
    .values({
      value1: "10 items",
      value2: "5 items",
      value3: "100 items",
      value4: "20 items",
      value5: "20 facts",
    })
    .sort((a, b) =>
      a.localeCompare(b, undefined, { numeric: true })
    )
);
    .as-console-wrapper { min-height: 100%!important; top: 0; }

    And in case the OP wanted to sort an array of equally structured object items, the above solution slightly changes too …

    console.log(
  [{
    value: '10 items',
  }, {
    value: '5 items',
  }, {
    value: '100 items',
  }, {
    value: '20 items',
  }, {
    value: '20 facts',
  }]
  .sort((a, b) =>
    a.value.localeCompare(b.value, undefined, { numeric: true })
  )
);
    .as-console-wrapper { min-height: 100%!important; top: 0; }
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