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I have two versions of a horizontal bar chart, stacked and paired (aka grouped). The code for each is stuffed into their own functions.

Refer to lines 35-43 (var stacked = function (){ ... }) and lines 117-121 (var paired = function (){ ... }) to see how the CSV is currently being parsed:

Unment line 197 and below to see the stacked version rendered. To do this I manually changed the data, not ideal.

GOAL: I want to parse the csv file and drop a column programmatically, rather than remove it manually and save 2 separate csv files.

I need to parse the csv and remove this with native d3 or javascript code, but how?

Shown in code.

I have:

Category,Total,Under $1000, ...
Music,14744,1434, ...
Art,12796,1216, ...

I need total removed:

Category,Under $1000, ...
Music,1434, ...
Art,1216, ...

I have two versions of a horizontal bar chart, stacked and paired (aka grouped). The code for each is stuffed into their own functions.

Refer to lines 35-43 (var stacked = function (){ ... }) and lines 117-121 (var paired = function (){ ... }) to see how the CSV is currently being parsed: http://tributary.io/inlet/8832116

Unment line 197 and below to see the stacked version rendered. To do this I manually changed the data, not ideal.

GOAL: I want to parse the csv file and drop a column programmatically, rather than remove it manually and save 2 separate csv files.

I need to parse the csv and remove this with native d3 or javascript code, but how?

Shown in code.

I have:

Category,Total,Under $1000, ...
Music,14744,1434, ...
Art,12796,1216, ...

I need total removed:

Category,Under $1000, ...
Music,1434, ...
Art,1216, ...

• javascript
• arrays
• csv
• d3.js

Share Improve this question Follow edited Nov 16, 2015 at 23:20 Brian Tompsett - 汤莱恩 5,8937272 gold badges6161 silver badges133133 bronze badges asked Feb 12, 2014 at 1:14 DeBraidDeBraid 9,44155 gold badges3333 silver badges4343 bronze badges

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4 Answers 4

Sorted by: Reset to default 2

If you have the CSV string in memory (a variable string), split on \n to get the lines, loop over each line and split on ,. This will give you an array of the column values for a given line.

Splice out the column you don't want, and then join line back with , - this will get you back a line of CSV data that you can push onto a result array.

Finally at the end, join the result array with \n and there you have it - a new string containing CSV data without column you don't want.

Note that this will not properly handle quotes / other gotcha's that e with CSV data, but if your data doesn't contain any of that you're in the clear.

---

Sample using map:

// raw CSV data from somewhere
var csv = 
'Category,Total,Under $1000\n' +
'Music,14744,1434,3450\n' +
'Art,12796,1216,7748\n';

// split on newlines, map over each line
var newCsv = csv.split('\n').map(function(line) {
    var columns = line.split(','); // get the columns
    columns.splice(1, 1); // remove total column
    return columns;
}).join('\n'); // join on newlines

console.log(newCsv);

http://jsfiddle/PZ9vM/

Add the column removal as suggested by Trevor to this and your csv parser can handle stuff like quotes as well.

Maybe just use some splicing and slicing?

var data;    //note, you're loading it in as a flat file with $.get()
$.get("/url/to/the/csvfile", function(d){
    data = d.splice("\n");
    var length = data.length; //so as to save loop runtime
    for (var i = 0; i < length; i ++){
        data[i] = data[i].splice(",")[0] + data[i].splice(",").slice(2)
        //this will split data[i] into the first piece before the ma
        //along with everything from the 2nd index to the end of the
        //array that was spliced with ","            
    }
}

splicing and slicing are so much fun...

edit: I forgot that you don't need to specify the end index with .slice().

Here's a nifty little vanilla JavaScript for you to remove a column from CSV data:

Working Demo

Code:

var csv = 
'Category,Total,Under $1000\n' +
'Music,14744,1434,3450\n' +
'Art,12796,1216,7748\n';

// Made it a function to make it reusable!
function removeColumn(data, colIndex) {
    var temp = data.split("\n");
    for(var i = 0; i < temp.length; ++i) {
        temp[i] = temp[i].split(",");
        temp[i].splice(colIndex,1);
        temp[i] = temp[i].join(","); // ment this if you want a 2D array
    }
    return temp.join("\n");     // returns CSV
    return temp;                // returns 2D array
    return d3.csv.parse(temp);  // returns a parsed object
}

console.log(removeColumn(csv,1));

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