After loading a csv, unable to convert string[] to float[]

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thunderba..

After loading a csv, unable to convert string[] to float[]

in Programming Questions • 1 year ago

I did some searches but couldn't find a solution to this.

I am loading a csv file and trying to create a separate array for each of the lines. When I try this, I get an error that says I cannot convert string[] to float[].

My original code before creating a csv file was structured like this:

float[] yearOne = {
2009, 4, 0, 1029.85, 1025.21, 1040.46, 1054.72, 1057.57, 1065.48, 1071.49, 1076.18, 1073.18, 1092.02, 1096.56, 1087.68, 1097.91, 1091.06, 1081.4, 1092.91, 1079.6, 1066.94, 1063.41, 1042.63, 1066.11, 1036.18
};
float[] yearTwo = {
2008, 3, 0, 1161.06, 1114.28, 1099.23, 1056.89, 996.23, 984.94, 909.92, 899.22, 1003.35, 998.01, 907.84, 946.43, 940.55, 985.4, 955.05, 896.78, 908.11, 876.77, 848.92, 940.51, 930.09, 954.09, 968.75
};
float[][] yearsAll = {
yearOne, yearTwo
};

I would like expand my data, so I created a csv file that looks like this:

2012,0,1440.67,1444.49,1445.75,1450.99,1461.4,1460.93,1455.88,1441.48,1432.56,,,,,,,,,,,,,,,
2011,0,1131.42,1099.23,1123.95,1144.04,1164.97,1155.46,1194.89,1195.54,1207.25,1203.66,1224.58,1200.86,1225.38,1209.88,1215.39,1238.25,1254.19,1229.05,1242,1284.59,1285.08,1253.3,,
2010,4,1141.2,1146.24,1137.03,1160.75,1159.97,1158.06,1165.15,1165.32,1169.77,1178.1,1173.81,1176.19,1184.71,1165.9,1178.17,1180.26,1183.08,1185.62,1185.64,1182.45,1183.78,1183.26,,
2009,3,1057.07,1029.85,1025.21,1040.46,1054.72,1057.57,1065.48,1071.49,1076.18,1073.18,1092.02,1096.56,1087.68,1097.91,1091.06,1081.4,1092.91,1079.6,1066.94,1063.41,1042.63,1066.11,1036.18,
2008,2,1164.74,1161.06,1114.28,1099.23,1056.89,996.23,984.94,909.92,899.22,1003.35,998.01,907.84,946.43,940.55,985.4,955.05,896.78,908.11,876.77,848.92,940.51,930.09,954.09,968.75

I then load the csv with the goal of having each line as it's own array, like the first block of code.

String[] lines = loadStrings("inx-test-one.csv");
for (int i = 0; i < lines.length; i++) {
float[][] arrayTest = { float(lines[i]) };
}

That's where I am stuck. Wouldn't this be the same as float[][] yearsAll = { yearOne, yearTwo}; ? When I println(lines[i]); I get the separate arrays like the individual ones up top.

How do I replicate the code in the first block using loadString and a loop?

Thanks, I hope this is clear.

Replies(10)

benja

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

Maybe there is some easier way to achieve this, but i ussually just do it with loops.

// load file
String[] lines = loadStrings("data.csv");

// get number of rows and columns
int rows = lines.length;
int cols = split(lines[0], ",").length;

// create array
float[][] floatArray = new float[rows][cols];

// iterate over lines
for (int i = 0; i < rows; i++) {

// split current line
String[] row = split(lines[i], ",");

// iterate over values
for (int j = 0; j< cols; j++) {

// parse and store the value
floatArray[i][j] = float(row[j]);
}
}

thunderba..

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

Thank you! this is exactly what I was trying to accomplish.

thunderba..

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

I have another question that relates to this.

I am plotting the data in each row. In my file, some rows contain more data than others. This displays "?" in my program since the values in the array are empty or NaN.

[0] "2012"
[1] "0"
[2] "1440.67"
[3] "1444.49"
[4] "1445.75"
[5] "1450.99"
[6] "1461.4"
[7] "1460.93"
[8] "1455.88"
[9] "1441.48"
[10] "1432.56"
[11] ""
[12] ""
[13] ""
[14] ""
[15] ""
[16] ""
[17] ""
[18] ""
[19] ""
[20] ""
[21] ""
[22] ""
[23] ""
[24] ""
[25] ""

I looked into the trim() function, but that seems to apply to whitespace within a String.

How do I check for these empty values?

PhiLho

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

if (row[j].length == 0)
// Do special treatment of this missing value

PhiLho

Re: Re: After loading a csv, unable to convert string[] to float[]

1 year ago

Yes, sorry, that's length(), I answered too fast...

thunderba..

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

Thanks PhiLho.

I am getting this error message: "length cannot be resolved or is not a field"

benja

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

Strings don't have the attribute "length", you have to call the function length().

if (row[j].length() == 0)

thunderba..

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

thanks benja.

What are my options now that I have identified it has zero?

Is it possible to remove it? or convert that 0 value to something unlike the data in my program like "99999" that way I can target it further down in the program.

Chrisir

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

when it has zero, just skip the line.

Thus floatArray will not be changed by this line.

// load file
String[] lines = loadStrings("data.csv");
// get number of rows and columns
int rows = lines.length;
int cols = split(lines[0], ",").length;
// create array
float[][] floatArray = new float[rows][cols];
// iterate over lines
for (int i = 0; i < rows; i++) {
if (!(row[j].length() == 0)) {
// split current line
String[] row = split(lines[i], ",");
// iterate over values
for (int j = 0; j< cols; j++) {
// parse and store the value
floatArray[i][j] = float(row[j]);
} // for
} // if
}
//

thunderba..

Re: After loading a csv, unable to convert string[] to float[]

1 year ago

Thanks all,

Chrisir: I had to change the location of the code you wrote in order for it to work:

String[] row = split(lines[i], ",");
// iterate over values
for (int j = 0; j < cols; j++) {
if (!(row[j].length() == 0)) {
// parse and store the value
floatArray[i][j] = float(row[j]);
}

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