如何按值按降序对文件大小字符串列表进行排序

Question

我正在尝试智能地对文件大小字符串的列表/数组进行排序（升序或降序）。字符串格式数字（带或不带小数）后跟空格，然后是单位。

例如 - ["5.1 GB", "19934563 B","224 kB","0.55 GB","0.04 kB","0.02 TB","2.4 MB",] 结果为 ["0.02 TB "、"5.1 GB"、"0.55 GB"、"19934563 B"、"2.4 MB"、"224 kB"、"0.04 kB"]

这是我目前所拥有的：

  
  if (!fileSizes.length) return "Enter an List to be Sorted";
  else {
    //Check input formart of strings
    let validFormat = fileSizes.map((file) => validFile(file));
    if (validFormat.includes(false)) return "Invalid Input format";
    else {
      let myfiles = reOrderFormat(fileSizes);
      if (descending === true) {
        sorter = MySort("TGMkB");
        let mysortedFiles = myfiles.sort(sorter);
        //sort by number for repeated file sizes
        let result = reOrderFormat(mysortedFiles);
        return result;
      } else {
        sorter = MySort("BkMGT");
        let mysortedFiles = myfiles.sort(sorter);
        //sort by number for repeated file sizes
        let result = reOrderFormat(mysortedFiles);
        return result;
      }
    }
  }
}

//Helper Functions for checking input format
//Regular expression for correct input format
function validFile(str) {
  let regEx = /^(-?\d*(\.\d+)?)\s((T|G|M|k)*B)$/;
  let valid = regEx.test(str);
  return valid;
}

//Checks if input is in right format
function validList(arr) {
  let validArray = arr.map((fileSiz) => validFile(fileSiz));
  return arr;
}

//Helper functions for sorting and reoredering input format
//Format reordering function
function reOrderFormat(arr) {
  let reOrdered = [];
  arr.map((file) => {
    let out = file.split(" ");
    let first = out[1];
    let second = out[0];
    let newOrder = first + " " + second;
    reOrdered.push(newOrder);
  });
  return reOrdered;
}

//Custom sorter
function MySort(alphabet) {
  return function (a, b) {
    var index_a = alphabet.indexOf(a[0]),
      index_b = alphabet.indexOf(b[0]);

    if (index_a === index_b) {
      // same first character, sort regular
      if (a < b) {
        return -1;
      } else if (a > b) {
        return 1;
      }
      return 0;
    } else {
      return index_a - index_b;
    }
  };
}

sort(
  ["5.1 GB", "19934563 B", "224 kB", "0.55 GB", "0.04 kB", "0.02 TB", "2.4 MB"],
  true
);

它不会对重复的单元进行相应的排序，还会混淆以字节为单位的长数字。

我需要帮助编写更高效的代码。

Answer 1

我能够在比较器排序的帮助下解决您的问题， 我按大小顺序构建全局数组：let sizes = ["B", "kB", "MB", "GB", "TB"];。 考虑您的主要功能称为 main 如下， 在 arr 上使用函数 sortSizes 后，返回数组应该是预期的数组：

function main() {
  let arr = ["5.1 GB", "19934563 B","224 kB","0.55 GB","0.04 kB","0.02 TB","2.4 MB",];
  let expected = ["0.02 TB", "5.1 GB", "0.55 GB", "19934563 B", "2.4 MB", "224 kB", "0.04 kB"];
  let new_arr = sortSizes(arr);
  console.log(new_arr);
  console.log(expected);
}

两个 console.log 都应该打印相同的排序数组。

// global array
let sizes = ["B", "kB", "MB", "GB", "TB"];

function sortSizes(arr) {

  // sort by comperator
  arr.sort(function(x, y) {
    var x_res = x.split(" "), y_res = y.split(" ");
    var x_value = x_res[0], x_unit = x_res[1];
    var y_value = y_res[0], y_unit = y_res[1];

    let amount = casting(x_unit, y_unit, x_value);

    if(amount < y_value) {
      return -1;
    } else if(x_value > y_value) {
      return 1;
    } else {
      return 0;
    }
  });

  return arr.reverse();
}

转换函数获取两个单位和数量，并将第一个数量转换为第二个数量后返回数量，例如：从5.1 GB到B应该是：5476083302.4 B.

function casting(unit_from, unit_to, amount) {
  var i = sizes.indexOf(unit_from);
  var j = sizes.indexOf(unit_to);
  var r;
  if(i < j) {
    r = j - i;
  } else {
    r = j - i;
  }

  var i = 0;
  if(r < 0) {
    r *= (-1);
    while(i < r) {
      amount *= 1024;
      i++;
    }
  } else {
    while(i < r) {
      amount /= 1024;
      i++;
    }
  }
  
  return amount;
}