Question

I can’t get my head around this one guys. I have a CSV file which I read from via AJAX, and I am creating an array from what is returned. My CSV file looks like this:

ID,name,address
0,john,123 fake st
1,bruce,123 fake st
2,john,124 fake st
3,fred,125 fake st
4,barry,126 fake st

I call it via an ajax function:

if (window.XMLHttpRequest) {
    var ajax = new XMLHttpRequest();
} else var ajax = new ActiveXObject("Microsoft.XMLHTTP");

function include(src) {
    ajax.open('GET', src, false);
    ajax.send(null);
    return ajax.responseText;
}

and loop through it like so:

var bsf = include('csv.csv');
// construct an array from the first line of the file
// and use that array to name the keys in all further arrays
var cols = bsf.split('\r\n');
var ln1 = cols[0].split(',');
// pull out each line from bsf and turn it into an array
var line = [];
var table = {};
var curRow = [];

for (i = 1; i < cols.length; i++) { // i = 1 so we can skip the 'title' csv line
    curRow = cols[i].split(',');

    for (j = 0; j < curRow.length; j++) {
        line[ln1[j]] = curRow[j];
    }

    table[curRow[0]] = line;
}
console.dir(table);

Instead of an object with one array for each row, I have 4 arrays that all contain the last row of the csv file. The nested for loop completes properly, and if I alert(line) before entering it into the table object, it returns the current line array correctly, but still does not assign that array to the object line.

Where I want

 table{
     0: [id: 0, name: 'john', address: '123 fake st'],
     1: [id: 1, name: 'bruce', address: '124 fake st'],
     ...}

I get

 table{
     4: [id: 4, name: 'barry', address: '126 fake st'],
     4: [id: 4, name: 'barry', address: '126 fake st'],
     etc.}

Any ideas? I get the feeling I am assigning them all correctly throughout the loop, but then on the last run through I am assigning them all wrongly and overwriting the correct ones.

Answer 1

Your problem is that you only have one line array that you refill over and over again:

for (j = 0; j < curRow.length; j++) {
    line[ln1[j]] = curRow[j];
}

and then you add that line array to the table in different places:

table[curRow[0]] = line;

The result is that each entry in table will be the last row from cols.

You simply need to put different arrays into table with something like this:

for (i = 1; i < cols.length; i++) {
    line   = [ ]; // <-------- This is the important part!
    curRow = cols[i].split(',');
    for (j = 0; j < curRow.length; j++) {
        line[ln1[j]] = curRow[j];
    }
    table[curRow[0]] = line;
}