Description
1. If the Lambda parameter generates a true value, the filter (Lambda that can generate a boolean result) will generate an element;
2. When false is generated , this element will no longer be used.
Example
Create a List collection:
List<String> stringCollection = new ArrayList<>(); stringCollection.add("ddd2"); stringCollection.add("aaa2"); stringCollection.add("bbb1"); stringCollection.add("aaa1"); stringCollection.add("bbb3"); stringCollection.add("ccc"); stringCollection.add("bbb2"); stringCollection.add("ddd1");
Filter's input parameter is Predicate, and Predicate is the intermediate operation of the assertion, which can filter out the necessary Collection elements. Its participation is also a Stream stream, and the filtered elements can be printed through the foreach terminal operation.
stringCollection .stream() .filter((s) -> s.startsWith("a")) .forEach(System.out::println); // "aaa2", "aaa1"
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