javascript - 如何将数组转换为集合

Question

我有一个与此类似的 .txt 文件。

ID;SubID;No.;Name;Min;Max;Default;Factor;Unit 
101;5;0;Gas flow time;0;100;0.1;10;s 
101;30;1;Start speed;20;200;120;1;m/s 
;;2;Start current;0;999;1.0;10;A

我使用 npm 包“fs” 和 readFile 导入此 .txt 文件，并使用 CSVToArray 将其转换为数组。在这里您可以找到我用于转换的代码。

function CSVToArray( strData, strDelimiter ){
// Check to see if the delimiter is defined. If not, then default to comma.
strDelimiter = (strDelimiter || ";");

// Create a regular expression to parse the CSV values.
var objPattern = new RegExp(
    (
        // Delimiters.
        "(\\" + strDelimiter + "|\\r?\\n|\\r|^)" +

            // Quoted fields.
        "(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|" +

            // Standard fields.
        "([^\"\\" + strDelimiter + "\\r\\n]*))"
    ),
    "gi"
);


// Create an array to hold our data. Give the array a default empty first row.
var arrData = [[]];
// Create an array to hold our individual pattern
// matching groups.
var arrMatches = null;

// Keep looping over the regular expression matches until we can no longer find a match.
while (arrMatches = objPattern.exec( strData )){

    // Get the delimiter that was found.
    var strMatchedDelimiter = arrMatches[ 1 ];

    // Check to see if the given delimiter has a length (is not the start of string) and if it matches
    // field delimiter. If id does not, then we know that this delimiter is a row delimiter.
    if (
        strMatchedDelimiter.length &&
        strMatchedDelimiter !== strDelimiter
    ){
        // Since we have reached a new row of data, add an empty row to our data array.
        arrData.push( [] );
    }
    var strMatchedValue;
    // Now that we have our delimiter out of the way, let's check to see which kind of value we
    // captured (quoted or unquoted).
    if (arrMatches[ 2 ]){
        // We found a quoted value. When we capture this value, unescape any double quotes.
        strMatchedValue = arrMatches[ 2 ].replace(
            new RegExp( "\"\"", "g" ),
            "\""
        );
    } else {
        // We found a non-quoted value.
        strMatchedValue = arrMatches[ 3 ];
    }
    // Now that we have our value string, let's add it to the data array.
    arrData[ arrData.length - 1 ].push( strMatchedValue );
}
// Return the parsed data.
return( arrData );

现在我想从 CSVToArray 返回的数组中创建一个名为 Parameter 的集合。该集合应如下所示:

// First entry: 
Parameter = {
    ID: 101;
    SubID: 5;
    No: 0;
    //...
}

// Second entry: 
Parameter = {
    ID: 101;
    SubID: 30;
    No:1;
    //...
}
...

有人知道将数组转换为集合的聪明方法吗？

非常感谢大家!

Answer 1

我建议您保持现有的 CSVToArray 不变，并添加另一个进行最终转换的函数:

function tableToObjectArray(arrData) {
    var keys = arrData[0];
    return arrData.slice(1).map(function (row) {
        return row.reduce(function (obj, val, idx) {
            obj[keys[idx]] = val;
            return obj;
        }, {});
    });
}

您可以使用 CSVToArray 的输出来调用它:

var arrData = CSVToArray(input, ';');
var objData = tableToObjectArray(arrData);

这是一个工作片段:

// Original left unchanged:
function CSVToArray( strData, strDelimiter ){
  // Check to see if the delimiter is defined. If not, then default to comma.
  strDelimiter = (strDelimiter || ";");

  // Create a regular expression to parse the CSV values.
  var objPattern = new RegExp(
    (
        // Delimiters.
        "(\\" + strDelimiter + "|\\r?\\n|\\r|^)" +
            // Quoted fields.
        "(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|" +
            // Standard fields.
        "([^\"\\" + strDelimiter + "\\r\\n]*))"
    ),
    "gi"
  );

  // Create an array to hold our data. Give the array a default empty first row.
  var arrData = [[]];
  // Create an array to hold our individual pattern
  // matching groups.
  var arrMatches = null;

  // Keep looping over the regular expression matches until we can no longer find a match.
  while (arrMatches = objPattern.exec( strData )){

    // Get the delimiter that was found.
    var strMatchedDelimiter = arrMatches[ 1 ];

    // Check to see if the given delimiter has a length (is not the start of string) and if it matches
    // field delimiter. If id does not, then we know that this delimiter is a row delimiter.
    if (
        strMatchedDelimiter.length &&
        strMatchedDelimiter !== strDelimiter
    ){
        // Since we have reached a new row of data, add an empty row to our data array.
        arrData.push( [] );
    }
    var strMatchedValue;
    // Now that we have our delimiter out of the way, let's check to see which kind of value we
    // captured (quoted or unquoted).
    if (arrMatches[ 2 ]){
        // We found a quoted value. When we capture this value, unescape any double quotes.
        strMatchedValue = arrMatches[ 2 ].replace(
            new RegExp( "\"\"", "g" ),
            "\""
        );
    } else {
        // We found a non-quoted value.
        strMatchedValue = arrMatches[ 3 ];
    }
    // Now that we have our value string, let's add it to the data array.
    arrData[ arrData.length - 1 ].push( strMatchedValue );
  }
  // Return the parsed data.
  return( arrData );
}

// New function added:
function tableToObjectArray(arrData) {
    var keys = arrData[0];
    return arrData.slice(1).map(function (row) {
        return row.reduce(function (obj, val, idx) {
            obj[keys[idx]] = val;
            return obj;
        }, {});
    });
}

// Sample data:
var input = `ID;SubID;No.;Name;Min;Max;Default;Factor;Unit 
101;5;0;Gas flow time;0;100;0.1;10;s 
101;30;1;Start speed;20;200;120;1;m/s 
;;2;Start current;0;999;1.0;10;A`;

// Convert to 2D array
var arrData = CSVToArray(input, ';');
// Convert to object array
var objData = tableToObjectArray(arrData);
// Output result:
console.log(objData);