CODEWITHSUNDEEP
arraysd3.js
Manny
Manny

Reputation: 127

D3.js unknown number of columns and rows

I m currently creating a chart(data from an external csv file) but I dont know beforehand the number of columns and rows. Could you maybe point me in the right direction as to where I could find some help(or some examples) with this issue?

Thank you

Upvotes: 3

Views: 2320

Answers (2)

Markus
Markus

Reputation: 528

In addition to Tom P's advice, it's worth noting that version 4 of D3 introduced a columns property, which you can use to create an array of column headers (i.e. the dataset's 'keys').

This is useful because (a) it's simpler code and (b) the headers in the array are in the same order that they appear in the dataset.

So, for the above dataset:

headers = data.columns

... creates the same array as:

headers = Object.keys(data[0])

... but the array of column names is in a predictable order.

Upvotes: 3

Tom P
Tom P

Reputation: 5659

d3.csv can help you here:

d3.csv('myCSVFile.csv', function(data){

  //the 'data' argument will be an array of objects, one object for each row so...

  var numberOfRows = data.length, // we can easily get the number of rows (excluding the title row)

      columns = Object.keys( data[0] ),  // then taking the first row object and getting an array of the keys

      numberOfCOlumns = columns.length;  // allows us to get the number of columns

});

Note that this method assumes that the first row (and only the first row) of your spreadsheet is column titles.

Upvotes: 8

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