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Asked: 2020-07-22 22:34:54 +0800 CST 2020-07-22 22:34:54 +0800 CST

Discriminate data according to two attributes

  • 772

I have the following arrangement:

let arreglo=[{'class':1,'var':1, 'valor':50},
            {'class':3,'var':2, 'valor':150},
            {'class':1,'var':2, 'valor':200},
            {'class':1,'var':1, 'valor':60},
            {'class':3,'var':2, 'valor':520},
            {'class':1,'var':2, 'valor':250}];

I want to discriminate by ordering according to the 'class' attribute

 [{'class':1,'var':1, 'valor':50},
        {'class':1,'var':2, 'valor':200},
        {'class':1,'var':1, 'valor':50},
        {'class':1,'var':2, 'valor':250}]

        [{'class':3,'var':2, 'valor':150},
        {'class':3,'var':2, 'valor':520}];

then discriminate according to the 'var' attribute to get

[{'class':1,'var':1, 'valor':50},
         {'class':1,'var':1, 'valor':50},
         {'class':1,'var':2, 'valor':200},
        {'class':1,'var':2, 'valor':250}]
        [{'class':3,'var':2, 'valor':150},
        {'class':3,'var':2, 'valor':520}];

my code is the following but what I do is discriminate and then I would have to join the arrays, I want a more efficient way.

let arreglo = [{'class': 1,'var': 1,'valor': 50},
  {'class': 3, 'var': 2,'valor': 150  },
  {'class': 1, 'var': 2,'valor': 200  },
  {'class': 1, 'var': 1,'valor': 60   },
  {'class': 3, 'var': 2,'valor': 520 },
  {'class': 1, 'var': 2,'valor': 250 }
];

function filtrarSegunVariable(arreglo, variable, condicion) {
  return arreglo.filter(function(x) {
    if (x[variable] === condicion) {
      return x;
    }
  })
}
let class1 = filtrarSegunVariable(arreglo, 'class', 1);
let class3 = filtrarSegunVariable(arreglo, 'class', 3);
console.log(filtrarSegunVariable(class1, 'var', 1));
console.log(filtrarSegunVariable(class1, 'var', 2));
console.log(filtrarSegunVariable(class3, 'var', 1));
console.log(filtrarSegunVariable(class3, 'var', 2));

note: values ​​1, 2, 3 must be strings

javascript

2 Answers

  1. To order handling of arrays there are many functions that can be used without having to resort to foror whilein this case you can use the Array.prototype.sort.

    The way this function is used is as follows:

    1) I declare my array:

     var myArray=[1,4,2,5,7,3];

    2) I sort it: myArray.sort((a,b)=>{ return ab; });

    the result would be: [1,2,3,4,5,7] What goes inside the sort is a callback that indicates how the array should be ordered, for more information see this link

    So to order your array you just have to adapt the callback to your needs:

     let arreglo=[{'class':1,'var':1, 'valor':50},
              {'class':3,'var':2, 'valor':150},
              {'class':1,'var':2, 'valor':200},
              {'class':1,'var':1, 'valor':60},
              {'class':3,'var':2, 'valor':520},
              {'class':1,'var':2, 'valor':250}];

 //primero ordenas por el parametro var, porque si ordenas por class primero
 //puede que al ordenar por var se desorganicen las class

 arreglo.sort((a,b)=>{return (a.var-b.var)});
 arreglo.sort((a,b)=>{return a.class-b.class});

 console.log(arreglo);

    Your arrangement is already ordered.

    • 2
  2. Best Answer

    You can pass the method sorta comparison function. So what you could do is pass a function that first sorts by comparing one value (class) and if they're equal, sorts by comparing by a second value (var) and if they're equal, sorts by comparing by a third value (value).

    Something like this:

    function(a,b) {
  // primer nivel: usando class
  if (a.class < b.class) {
    return -1;
  } else if (a.class == b.class) {
    // si son iguales = segundo nivel: usando var
    if (a.var < b.var) {
      return -1;
    } else if (a.var == b.var) {
      // si son iguales = tercer nivel: usando valor
      return a.valor >= b.valor;
    } else {
      return 1;
    }
  } else {
    return 1;
  }
}

    Here you can see it working:

    let arreglo = [
  {'class': 1, 'var': 1, 'valor': 50  },
  {'class': 3, 'var': 2, 'valor': 150 },
  {'class': 1, 'var': 2, 'valor': 200 },
  {'class': 1, 'var': 1, 'valor': 60  },
  {'class': 3, 'var': 2, 'valor': 520 },
  {'class': 1, 'var': 2, 'valor': 250 }
];

var arreglo2 = arreglo.sort(function(a,b) {
  if (a.class < b.class) {
    return -1;
  } else if (a.class == b.class) {
    if (a.var < b.var) {
      return -1;
    } else if (a.var == b.var) {
      return a.valor >= b.valor;
    } else {
      return 1;
    }
  } else {
    return 1;
  }
});

console.log(arreglo2);

    And here you can see how it also works if the values ​​were strings:

    let arreglo = [
  {'class': '1', 'var': 'A', 'valor': 50  },
  {'class': '3', 'var': 'B', 'valor': 150 },
  {'class': '1', 'var': 'B', 'valor': 200 },
  {'class': '1', 'var': 'A', 'valor': 60  },
  {'class': '3', 'var': 'B', 'valor': 520 },
  {'class': '1', 'var': 'B', 'valor': 250 }
];

var arreglo2 = arreglo.sort(function(a,b) {
  if (a.class < b.class) {
    return -1;
  } else if (a.class == b.class) {
    if (a.var < b.var) {
      return -1;
    } else if (a.var == b.var) {
      return a.valor >= b.valor;
    } else {
      return 1;
    }
  } else {
    return 1;
  }
});

console.log(arreglo2);

    • 1