how to get data with tsv or csv to array in d3.js from a txt file?

问题

I am using this to parse a csv file and create an array data as specified in d3 docs:

d3.tsv("classes_h.txt", function(data) { 
    data.forEach(function(d) { 
        console.log(data[0]);
        console.log("lol");
    });
    console.log(data[0]);
});

d3.tsv("classes_h.txt", function(data) { 
    console.log(data[0]);
});

However I get undefined in the console when I call the data[0]. I've also tried writing out "data instead of "data[0]" which result in me getting an empty array -> []:

My txt file looks like this: http://puu.sh/7LrRm.png

Everything is seperated with a tab, so tsv is what I'm using and if I have understood it correctly, whether tsv or csv is used depends on the format the data is in?

Thanks in advance.

回答1:

SOLVED

TSV doesn't just take tab seperated elements a throw them into an array. You the format to look like this:

Group1 Group2 Group3
data1  data1  data1
data2  data2  data2
data3  data3  data3

Then you can print out and verify that the data is loaded:

data.forEach(function(d) { 
    console.log(d);
});

When printing out the entire data D3 will create an objects that each have a Group bound with all of it's data. Here's the output of my example:

Object {Group1: "data1", Group2: "data1", Group3: "data1"}
Object {Group1: "data2", Group2: "data2", Group3: "data2"}
Object {Group1: "data3", Group2: "data3", Group3: "data3"}

Those the objects are equivalent to data[0], data[1] and data[2], which leaves group1, group2 and group3.

回答2:

Is this localy hosted? If it is are you loading the page with the file:// protocol or is it been served over http (eg http://localhost:8080).

If it is using file:// then you will be having problems as the browser will not allow the file to be loaded with a XMLHttpRequest which d3.tsv() uses to fetch the file.

Alternatively follow Lars' advice and check for an error

d3.tsv("file.tsv", function(error, data){
    if(error){
        return console.log(error);
    }
    // there was no error
});

回答3:

Changing the data[0] to d.header of data you want displayed should work.

d3.tsv("classes_h.txt", function(data) { 
data.forEach(function(d) { 
    console.log(d.*displaydata*);
    console.log("lol");
});

来源：https://stackoverflow.com/questions/22690168/how-to-get-data-with-tsv-or-csv-to-array-in-d3-js-from-a-txt-file

标签

javascript

arrays

csv

d3.js

tsv