Python Pandas equivalent in JavaScript

Question

With this CSV example:

   Source,col1,col2,col3
   foo,1,2,3
   bar,3,4,5

The standard method I use Pandas is this:

1. Parse CSV<

Answer 1

It's pretty easy to parse CSV in javascript because each line's already essentially a javascript array. If you load your csv into an array of strings (one per line) it's pretty easy to load an array of arrays with the values:

var pivot = function(data){
    var result = [];
    for (var i = 0; i < data.length; i++){
        for (var j=0; j < data[i].length; j++){
            if (i === 0){
                result[j] = [];
            }
            result[j][i] = data[i][j];
        }
    }
    return result;
};

var getData = function() {
    var csvString = $(".myText").val();
    var csvLines = csvString.split(/\n?$/m);

    var dataTable = [];

    for (var i = 0; i < csvLines.length; i++){
        var values;
        eval("values = [" + csvLines[i] + "]");
        dataTable[i] = values;
    }

    return pivot(dataTable);
};

Then getData() returns a multidimensional array of values by column.

I've demonstrated this in a jsFiddle for you.

Of course, you can't do it quite this easily if you don't trust the input - if there could be script in your data which eval might pick up, etc.