Filter List of String arrays based on value in String array

Question

I have a list of string arrays that I am reading from a csv file that I want to filter using Java. I would like to retrieve the whole String array that contains a particular value.

List<String[]> csvData = readAllData("src/test/resources/data.csv", ';');

The output after printing:

[24, Desnoyers Claude, 1030311841077]
[25, Doiron Fletcher, 1680375680748]
[63, Mainville Agathe, 2680408184680]
[363, Pinette Searlas, 1940914809627]

For instance, I would like to retrieve the whole array that contains a particular name, like Doiron Fletcher, regardless of its index. I know that I can use stream in Java 8, but I am fairly new to Java and don't really know how to do it for lists of string arrays. Any ideas on how I can do this?

dimnnv · Accepted Answer · 2022-12-19 15:01:12Z

1

You can take knowledge of that "name" is the second element of your array.

Before Java 17:

List<String[]> filteredData = csvData.stream()
        .filter(item -> "Doiron Fletcher".equals(item[1]))
        .collect(Collectors.toList()));

Java 17+:

List<String[]> filteredData = csvData.stream()
        .filter(item -> "Doiron Fletcher".equals(item[1]))
        .toList());

Or if you need only one (e.g. the first) row:

String[] foundRow = csvData.stream()
        .filter(item -> "Doiron Fletcher".equals(item[1]))
        .findFirst().orElse(null);

edited Dec 19, 2022 at 15:01

answered Dec 19, 2022 at 14:41

dimnnv

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2 Comments

WJS Over a year ago

Note: toList() has been around since Java 16.

dimnnv Over a year ago

Strictly speaking yes. But it is a somewhat 'minor' Java revision and most developers start working either with Java 8 (or earlier) / 11 or with 17. I think memorizing too many versions would be a bit overcomplication for beginners.

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