Enthuware

The map method is meant to replace one element of stream with another. While the flatMap method replaces one element of a stream with elements of a new stream generated using the original element. Therefore, map is not useful here.

Stream<String> strm = sentences.stream()
.map(str->Stream.of(str.split("[ ,.!?\r\n]")))
.filter(s->s.length()>0).distinct();

schchen2000 wrote: What did you mean when you said "The map method is meant to replace one element of stream with another."?

Code: Select all

Stream<String> strm = sentences.stream()
.map(str->Stream.of(str.split("[ ,.!?\r\n]")))
.filter(s->s.length()>0).distinct();

This answer choice is wrong because the output of map will be a stream and each entry in the stream is in the form of String[], not individual strings.

Is that correct?

What we want out of a mapping in this question is individual strings leaving the mapping. We then want to apply some conditions to those strings leaving the mapping in order to do filtering prior to choosing only distinct items.

Is my understanding correct?

Thanks.

Schmichael

admin wrote: ↑

Wed Jun 08, 2016 2:12 am

schchen2000 wrote:

Code: Select all

Stream<String> strm = sentences.stream()
.map(str->Stream.of(str.split("[ ,.!?\r\n]")))
.filter(s->s.length()>0).distinct();

This answer choice is wrong because the output of map will be a stream and each entry in the stream is in the form of String[], not individual strings.

Is that correct?

Correct.

String sentence1 = "Carpe diem. Seize the day, boys. Make your lives extraordinary.";
String sentence2 = "Frankly, my dear, I don't give a damn!";
String sentence3 = "Do I look like I give a damn?";
List<String> sentences = Arrays.asList(sentence1, sentence2, sentence3);

sentences.stream()
	.map(str->Stream.of(str.split("[ ,.!?\r\n]")))
	.peek(x -> x.forEach(System.out::print))
	.count();