I'm trying to read a csv file and convert its String values to double.
public void trq() throws IOException, ParseException {
Test4 obj = new Test4();
String path = "transposedData1.csv";
BufferedReader readerBuffer = new BufferedReader(new FileReader(path));
String line;
List<Double> results = new ArrayList<Double>();
while ((line = readerBuffer.readLine()) != null) {
if(!line.contains("NA")) {
ArrayList<String> data_per_class = convertCSVtoArrayList11(line);
List<Double> doubleList = data_per_class.stream()
.map(Double::parseDouble)
.collect(Collectors.toList()); // the error here
// do other things
}
}
}
public static ArrayList<String> convertCSVtoArrayList11(String pathCSV) {
ArrayList<String> result = new ArrayList<String>();
if (pathCSV != null) {
String[] splitData = pathCSV.split("\\s*,\\s*");
for (int i = 0; i < splitData.length; i++) {
if (!(splitData[i] == null) || !(splitData[i].length() == 0)) {
result.add(splitData[i].trim());
}
}
}
return result;
}
The CSV file looks like:
1.0 8.0 4.0 6.0
3.0 2.0 1.0 5.0
7.0 1.0 8.0 1.0
1.0 2.0 1.0 4.0
Note that there is no header. The file starts with values with no headers. The error I am getting is:
Exception in thread "main" java.lang.NumberFormatException: For input string: ""1.0""
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043)
at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
at java.lang.Double.parseDouble(Double.java:538)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:566)
at Test4.trq(Test4.java:1063) \\ I mentioned that in the code above
Do you have any idea how to solve this?
Replace
pathCSV.split("\\s*,\\s*");
with
pathCSV.split("\\s+");
So that the numbers are split on spaces. Currently, they are getting stored into result with extra "
eg ""1.0""
which should be stored as "1.0"
.
Based on the error message you can see, that the number is actually aurrounded by a pair of quotation marks, which probably causes the call to fail.
A quick fix would be to use asString = substring(1, asString.length() - 2);
, with asString
being the string that you want to parse to a double.
Use result.add(splitData[i].trim(). replaceAll("/"","") )
before returning
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