How to read in a csv with multiple columns with SuperCSV

Question

I have a CSV file containing 2 columns (1 containing a list of words, another with the frequency they are used in a text document). I was curious the best way to read that in an ArrayList of type object using SuperCSV. Thanks in advance.

Answer 1

I'm assuming you've read the documentation and examples on the Super CSV website?

If you use CsvListReader with cell processors (I'd recommend something like new CellProcessor[]{new NotNull(), new NotNull(new ParseInt())} then you'll get a List of Objects - but you will have to cast to the appropriate type when getting the values out of the List. If you don't use cell processors you'll get a List of Strings and have to convert the count to an Integer- it's up to you but I prefer to let Super CSV to all the conversions.

You can always use CsvBeanReader to avoid any casting - you'll just have to create a bean with 2 fields: word (String) and count (Integer) and their getters/setters.

It's totally up to you - there really is no 'best way', but using a CSV library is a good practice. In terms of storing the result of the word frequencies, I'd recommend a Map<String,Integer> (word -> count).

Answer 2

First setup a Processor:

    private static CellProcessor[] getProcessors() {

        final CellProcessor[] processors = new CellProcessor[] {
                new NotNull(new ParseInt()), 
                new NotNull(), 
                new NotNull(), 
                new Optional(new ParseLong())

        };
        return processors;
    }

Next up: Build a reader ( there are 3 types) so for our examples we can use this:

listReader = new CsvListReader(
new InputStreamReader(new FileInputStream(CSVFILE, CHARSET),CsvPreference.TAB_PREFERENCE);
listReader.getHeader(false);
while ((listReader.read(processors)) != null) {}

And you are done, good luck.