How to check if element exists using lambda expression?

Question

In particular, I have a TabPane, and I would like to know if there is an element with a specific identifier in it.

So, I would like to do this using the lambda expression in Java:

boolean idExists = false; String idToCheck = "someId"; for (Tab t : tabPane.getTabs()){ if(t.getId().equals(idToCheck)) { idExists = true; } }

+54

java lambda java-8

Miljac Apr 11 '14 at 6:19 06:19

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2 answers

Although the accepted answer is correct, I will add a more elegant version (in my opinion):

 boolean idExists = tabPane.getTabs().stream() .map(Tab::getId) .anyMatch(idToCheck::equals);

Do not neglect the use of Stream # map () , which allows you to smooth the data structure before applying Predicate .

+19

jFrenetic Dec 12 '16 at 19:45

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Masudul · Accepted Answer · 2014-04-11 06:24

Try using anyMatch Lambda expressions. This is a much better approach.

  boolean idExists = tabPane.getTabs().stream() .anyMatch(t -> t.getId().equals(idToCheck));