I have following statement creating an array of array of String:
String[][] strArr = {{"Jazz","80"},{"sam","90"},{"shaam","80"},{"aditya","100"}};
Would it be possible to get stream as following? I tried it in Eclipse but got an error.
Stream<String,String> streamObj = Arrays.stream(strArr);
Tried to search on net but mostly results were showing to get stream from 1-D array of strings as shown below:
String[] stringArr = {"a","b","c","d"};
Stream<String> str = Arrays.stream(stringArr);
There is no feasible representation such as Stream<String, String> with the java.util.stream.Stream class since the generic implementation for it relies on a single type such as it declared to be:
public interface Stream<T> ...
You might still collect the mapping in your sub-arrays as a key-value pair in a Map<String, String> as:
Map<String, String> map = Arrays.stream(strArr)
.collect(Collectors.toMap(s -> s[0], s -> s[1]));
To wrap just the entries further without collecting them to a Map, you can create a Stream of SimpleEntry as :
Stream<AbstractMap.SimpleEntry<String, String>> entryStream = Arrays.stream(strArr)
.map(sub -> new AbstractMap.SimpleEntry<>(sub[0], sub[1]));
You can define a POJO called StringPair and map the stream.
public class PairStream {
public static void main(String[] args) {
String[][] strArr = {{"Jazz","80"},{"sam","90"},{"shaam","80"},{"aditya","100"}};
Arrays.stream( strArr ).map( arr -> new StringPair(arr) ).forEach( pair -> System.out.println(pair) );
}
private static class StringPair {
private final String first;
private final String second;
public StringPair(String[] array) {
this.first = array[0];
this.second = array[1];
}
@Override
public String toString() {
return "StringPair [first=" + first + ", second=" + second + "]";
}
}
}
As well as you can use Apache Commons lang Pair
public class PairStream {
public static void main(String[] args) {
String[][] strArr = {{"Jazz","80"},{"sam","90"},{"shaam","80"},{"aditya","100"}};
Arrays.stream( strArr ).map( arr -> Pair.of(arr[0],arr[1]) ).forEach( pair -> System.out.println(pair) );
}
}
Arrays.stream(strArr).flatMap(Arrays::stream)