how to convert created new list of matched values from existing list using java stream-CodePudding

Currently I used nested for-each loop to achieve the same.

List<String> valueListToBeFilter = Arrays.asList("8 digit mobile number", "Please enter mobile number.");
List<String> newfoundValueList = new ArrayList<>();

for (String value : valueListToBeFilter) {
    for (WebElement element : _webElementsErrorList) {
        if (element.getText().contains(value))
            newfoundValueList.add(element.getText());
    }
}
newfoundValueList.forEach(System.out::println);

I am getting the required result, but how to achieve the same using stream

CodePudding user response：

It may be better to swap map and filter in the "nested" stream to reduce the code a little bit more, but generally it's a minor improvement:

List<String> newfoundValueList = valueListToBeFilter
    .stream()
    .flatMap(value -> _webElementsErrorList
        .stream()
        .map(WebElement::getText)
        .filter(elementText -> elementText.contains(value))
    )
    .collect(Collectors.toList());

CodePudding user response：

Should work with .flatMap and another stream of the WebElement-List like this:

List<String> newfoundValueList = valueListToBeFilter.stream()
    .flatMap(value -> _webElementsErrorList.stream()
        .filter(element -> element.getText().contains(value))
        .map(element -> element.getText()))
    .collect(Collectors.toList());