elasticsearch/docs/painless/painless-lambdas.asciidoc

[[painless-lambdas]]
=== Lambdas
Lambda expressions and method references work the same as in https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html[Java].

[source,painless]
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list.removeIf(item -> item == 2);
list.removeIf((int item) -> item == 2);
list.removeIf((int item) -> { item == 2 });
list.sort((x, y) -> x - y);
list.sort(Integer::compare);
---------------------------------------------------------

You can make method references to functions within the script with `this`,
for example `list.sort(this::mycompare)`.