Read selected column in javascript from csv

Question

I used a javascript to upload a csv file and did some cleaning, I would like to only show 1 column out of everything in the csv file, any advice?

Here is my javascript

function Upload() {
    var fileUpload = document.getElementById("fileUpload");
    var regex = /^([a-zA-Z0-9\s_\\.\-:])+(.csv|.txt)$/;

    if (regex.test(fileUpload.value.toLowerCase())) {
        if (typeof (FileReader) != "undefined") {
            var reader = new FileReader();
            reader.onload = function (e) {
                var table = document.createElement("table");
                var rows = e.target.result.split("\n");
                for (var i = 0; i < rows.length; i++) {
                    var cells = rows[i].split(",");
                    if (cells.length > 1) {
                        var row = table.insertRow(-1);
                        for (var j = 0; j < cells.length; j++) {
                            var cell = row.insertCell(-1);
                            cell.innerHTML = cells[j];
                        }
                    }
                }
                var dvCSV = document.getElementById("dvCSV");
                dvCSV.innerHTML = "";
                dvCSV.appendChild(table);
            }
            reader.readAsText(fileUpload.files[0]);
        } else {
            alert("This browser does not support HTML5.");
        }
    } else {
        alert("Please upload a valid CSV file.");
    }
}

HTML

              <input type="file" id="fileUpload" />
              <input type="button" id="upload" value="Upload" onclick="Upload()" />
              <div id="dvCSV">

Any advice will be greatly appreciated. Thanks in advance.

Why don't you use external CSV libraries that are browser compatible? There is no need to reinvent the wheel. — Yak O'Poe
– Yak O'Poe, Commented May 16, 2020 at 15:29

BoltKey · Accepted Answer · 2020-05-16 15:27:02Z

1

Instead of iterating over all the row cells, just output the one you want:

var targetIndex = rows[0].indexOf("Column name");
for (var i = 0; i < rows.length; i++) {
     var cells = rows[i].split(",");
     if (cells[targetIndex]) {
          var row = table.insertRow(-1);
          var cell = row.insertCell(-1);
          cell.innerHTML = cells[targetIndex];
     }
}

answered May 16, 2020 at 15:27

BoltKey

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