getHeaders in CsvReader

[xavier-figueroa]

I havent seen any easy way to get the existing headers for a file. It would be great to get a list/map with all the headers (first row)

[osiegmar]

You can call getHeader() or getFieldsAsMap() on NamedCsvRecord records.

Example:

Path file = Path.of("test.csv");
try (CsvReader<NamedCsvRecord> csv = CsvReader.builder().ofNamedCsvRecord(file)) {
    for (NamedCsvRecord rec : csv) {
        List<String> header = rec.getHeader();
        Map<String, String> fieldMap = rec.getFieldsAsMap();
        // ...
    }
}

[xavier-figueroa]

Thank you so much for your response. Im using getFieldsAsMap but that requires the csv file to have at least one row other than the header. If we only have the header it will never enter the foreach section.

The following code does more or less what I need but it does not work with NamedCsvRecords

        try (CsvReader<CsvRecord> csv = CsvReader.builder().ofCsvRecord(csvFile2.toPath())) {
            System.out.println(csv.iterator().next().getFields());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

I also tried the following but it does not work:

        try (CsvReader<NamedCsvRecord> csv = CsvReader.builder().ofNamedCsvRecord(csvFile.toPath())) {
            System.out.println(csv.iterator().next().getFields());
            System.out.println(csv.iterator().next().getHeader());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

it throws:
Exception in thread "main" java.util.NoSuchElementException

I think it would be great if we could call getHeader (List<String) or getHeaderAsMap(Map<String, Integer> name->position), directly on any reader without the need of creating an iterator. It seems the header is stored in NamedCsvRecordHandler but Im not clear how to access it

Regards

[osiegmar]

Thanks for this additional info. Currently it is not possible to access the header of a file that contains nothing more than the header via NamedCsvRecord. I transferred this to #147.