名单 <String[]> 浮动阅读CSV

Question

I'm trying to read a csv file to a 2D array in Java.

So far I manage to follow some stackoverflow examples and successfully read the .csv using opencsv-3.2.

    CSVReader csvReader = new CSVReader(new FileReader(new File("file.txt")));
    List<String[]> list = csvReader.readAll();

    String[][] dataArr = new String[list.size()][];
    dataArr = list.toArray(dataArr);

However I would like to dataArr be on float type and not on String. I probably imagine that we have to convert the String list to float, but despite several attempts and some reading I still do not have success. Thanks

Answer 1

The toArray() method of the List class is definitely not what you are looking for...

You are going to have to manually loop through the list and parse each record in the row individually (assuming you don't have access to Java 8).

Something like:

float[][] dataArr = new float[list.size()][];

for(int row = 0; row<list.size(); row++){
    String [] thisRowStrings = list.get(row);
    float[] thisRowFloats = new float[thisRowStrings.length];
    for(int c=0; c<thisRowStrings.length; c++){
       thisRowFloats[c]=Float.parseFloat(thisRowStrings[c]);
    } 
    dataArr[row]=thisRowFloats;
}