Passing arbitrary column values to D3 visualization when reading data file

Question

I am using the D3 histogram visualization and want to pass headers in that are not necessarily named \"letter\" or \"frequency.\" If I attempt to change the column attributes i

Answer 1

Square brackets allow the passing of variables.

d3.tsv(datapath, type, function(error, data) {
x.domain(data.map(function(d) { return d[columnname1]; }));
y.domain([0, d3.max(data, function(d) { return d[columnname2]; })]);