Float / Array error reading from CSV - arrays

Question

I'm missing something fundamental here but I can't seem to find out what from all my research.
I have imported a csv file, split the string into floats, and now wish to connect all points to all other points with a line. My code is as follows:
String [] data;
void setup () {
size(300, 300);
background(255);
data = loadStrings("points.csv");
for (int i = 0; i < data.length; i++) {
String [] fields = split(data[i], ',');
float t = float(fields[0]);
float n = float(fields[1]);
float x = float(fields[2]);
float y = float(fields[3]);
ellipse(x, y, 10, 10);
line(x, y, x[i], y[i]);
}
}
The error message is "The type of expression must be an array type but it resolved to float"
I'm sure this is extremely basic but, I dont understand why x[i] or y[i] are not seen as an array type.
I would really appreciate any help with this. Many thanks in advance.
Sam
*UPDATE***
An exract from the points.csv file is as follows:
219185750 rabih_takkoush 20.88521 19.49821
219185716 MoustaphaAjram 100.870896 59.515259
219185709 jinanejghosh 56.886441 35.489087
219185557 MoustaphaAjram 34.870904 78.515243
219185555 Mohammad8Itani 12.8946 49.48179
What I am trying to accomplish is plotting the various geolocations (whereby col 3 = x, col 4 = y) and then connecting all points with all other points with a line.
The following script works plotting all locations specified in the array within the script:
float[] x = { 50, 100, 150, 200,20,20 };
float[] y = { 10, 30, 20, 250,20,90 };
void setup () {
size(300, 300);
background(255);
}
void draw() {
for (int i = 0; i < x.length; i++) {
ellipse(x[i], y[i], 10, 10);
for (int j = 0; j < x.length; j++) {
line(x[j], y[j], x[i], y[i]);
}
}
}
What I wish to do is do the same, but reading columns 3 and 4 of the csv file.

Answer 1

You're splitting your data into iteration-scoped floats, then you try to access them as if they're both floats as well as arrays in your line() call. Try this:
String[] data;
float[] x, y, t, n;
void setup () {
size(300, 300);
data = loadStrings("points.csv");
int len = data.length;
x = new float[len];
x = new float[len];
t = new float[len];
n = new float[len];
for (int i=0; i<len; i++) {
String line = data[i];
String[] fields = split(line, ',');
t[i] = float(fields[0]),
n[i] = float(fields[1]),
x[i] = float(fields[2]),
y[i] = float(fields[3]);
}
// don't put draw instructions in setup,
// put them in draw. if you want to run once,
// issue a noLoop() so that happens.
noLoop();
}
void draw() {
float prevx = x[0], prevy = y[0];
for (int i=0, last=x.length; i<last; i++) {
ellipse(x[i], y[i], 10, 10);
line(prevx,prevy, x[i],y[i]);
prevx=x[i];
prevy=y[i];
}
}
Now we're storing the data from CVS in linked arrays that we can access throughout the sketch, rather than throwing them away after setup().

Answer 2

ok so if you go with the first code you made, you only need to change a few things, here is what you can do:
float[] x;
float[] y;
string[] data;
void setup () {
size(300, 300);
background(255);
data = loadStrings("points.csv");
x = new float[data.length];
y = new float[data.length];
for (int i = 0; i < data.length; i++) {
String [] fields = split(data[i], ',');
float t = float(fields[0]);
float n = float(fields[1]);
float x = float(fields[2]);
float y = float(fields[3]);
}
}
void draw() {
for (int i = 0; i < x.length; i++) {
ellipse(x[i], y[i], 10, 10);
for (int j = 0; j < x.length; j++) {
line(x[j], y[j], x[i], y[i]);
}
}
}
As you can see nothing really new, it's a mix between your initial code and the one you made for the csv.
And actually you mainly needed to declare your x and y variables as float[] instead of just float. But also there were some changes to make in the loop.
In this code you load the data in your arrays first (exactly like you did by declaring array's values in your code, but this time you read these values from your file), and then call your draw method as before.
hope it works now