When I create a LinkedList and add some values like this:

List<String> l = new LinkedList<>();
l.add("I");
l.add("have");
l.add("eaten");
l.add("!");

How to count the occurrence of char "e" using lambda or other method?

CodePudding user response：

Stream the contents of the List. Map each value to an int by replacing all non-'e' values with nothing and taking the length of the resulting String. Take the sum() of all such lengths. Like,

int count = l.stream().mapToInt(s -> s.replaceAll("[^e]", "").length()).sum();