#Java - Code Snippets for '#Collectors' - 11 code snippet(s) found |
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Sample 1. Get all elements greater than 2, sort them and then push them to a new set, using Lambda Expression | |
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// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Set the predicate or the condition for filtering the elements.
Predicate<Integer> moreThan2Pred = (p) -> (p > 1);
// Use Filter to refine the element set, sort to Sort and Collectors.toSet to get a set out of Stream.
intSet = intSet.stream().filter(moreThan2Pred).sorted().collect(Collectors.toSet());
System.out.println(intSet); // Prints [2, 3, 4]
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Like Feedback lambda expression collections set hashset generics stream predicate filter sort java.util.hashset java.util.stream.Collectors |
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Sample 2. Combine two Summaries and Generate a new Summary using Lambda Expression | |
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// Populate a List using Set elements.
// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
Set<Integer> intSet2 = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
intSet2.add(1);
intSet2.add(2);
intSet2.add(3);
intSet2.add(4);
// Use the stream and collectors to Summarize all Integer elements
IntSummaryStatistics summary = intSet.stream().collect(Collectors.summarizingInt(p->((Integer)p)));
summary.combine(intSet2.stream().collect(Collectors.summarizingInt(p->((Integer)p))));
System.out.println(summary); // Prints IntSummaryStatistics{count=8, sum=20, min=1, average=2.500000, max=4}
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Like Feedback lambda expression collections set hashset generics stream collectors Collectors.summarizingInt summary.combine java.util.hashset java.util.stream.Collectors java.util.IntSummaryStatistics |
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Sample 3. Find the Average of all collection elements using Lambda Expressions | |
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// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Use the stream and Collector to find the average of all elements.
System.out.println(intSet.stream().collect(Collectors.averagingInt(p->((Integer)p)))); Prints 2.5
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Like Feedback lambda expression collections set hashset generics stream collector |
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Sample 4. Group Elements by even or Odd using Lambda Expressions | |
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// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Use the stream and Collector to Group by Even and Odd
System.out.println(intSet.stream().collect(Collectors.groupingBy(p->((Integer)p)%2))); Prints {0=[2, 4], 1=[1, 3]}
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Like Feedback lambda expression collections set hashset generics stream collectors Collectors.groupingBy |
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Sample 5. Sum all collection elements using Lambda Expressions | |
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// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Use the stream and collectors to sum all elements.
System.out.println(intSet.stream().collect(Collectors.summingInt(p->(Integer)p)));
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Like Feedback lambda expression collections set hashset generics stream collectors Collectors.groupingBy |
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Sample 6. Get the complete Summary of Collection Elements using Lambda Expressions | |
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// Populate a List using Set elements.
// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Use the stream and collectors to Summarize all Integer elements
System.out.println(intSet.stream().collect(Collectors.summarizingInt(p->((Integer)p)))); // Prints IntSummaryStatistics{count=4, sum=10, min=1, average=2.500000, max=4}
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Like Feedback lambda expression collections set hashset generics stream collectors Collectors.summarizingInt |
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Sample 7. Write a Program that gets a set of numbers , filters out the non prime numbers , calculate the factorial of each prime number and then finds the average of all factorials using Lambda expressions | |
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public class BuggyBread1 {
public static void main(String args[]) {
// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
intSet.add(5);
double averageOfNonPrimeFactorials = intSet.stream().filter(p->checkIfPrime(p)).collect(Collectors.averagingInt(p->calculateFactorial(p)));
System.out.println(averageOfNonPrimeFactorials );
}
static private boolean checkIfPrime(int num){
for(int count=2;count < num;count++){
if(num % count == 0){
return false;
}
}
return true;
}
static private int calculateFactorial(int num){
int factorial = 1;
for(int count=num;count > 0;count--){
factorial = factorial * count;
}
return factorial;
}
}
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Like Feedback java 8 lambda expressions lambda filter Collectors factorial prime number |
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Sample 8. Populate a List using Set elements and Lambda Expression | |
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// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Use the stream and collectors to get List out of Set
List li = intSet.stream().collect(Collectors.toList());
System.out.println(li); // Prints [1, 2, 3, 4]
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Like Feedback lambda expression collections set hashset generics stream collectors Collectors.toList |
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Sample 9. Create a Map using Set elements using Lambda Expression | |
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// Declare and Initialize the Collection
Set<Integer> intSet = new HashSet<Integer>();
// Add Elements
intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
// Use the stream and collectors to get a Map out of Set
System.out.println(intSet.stream().collect((Collectors.toMap(p->(Integer)p,q->((Integer)q)*500)))); // Prints {1=500, 2=1000, 3=1500, 4=2000}
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Like Feedback lambda expression collections set hashset generics stream collectors |
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Sample 10. Code Sample / Example / Snippet of org.apache.storm.task.OutputCollector | |
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public void shouldEmitNothingIfNoObjectHasBeenCountedYetAndTickTupleIsReceived() {
Tuple tickTuple = MockTupleHelpers.mockTickTuple();
RollingCountBolt bolt = new RollingCountBolt();
Map conf = mock(Map.class);
TopologyContext context = mock(TopologyContext.class);
OutputCollector collector = mock(OutputCollector.class);
bolt.prepare(conf, context, collector);
bolt.execute(tickTuple);
verifyZeroInteractions(collector);
}
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Like Feedback org.apache.storm.task.OutputCollector |
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Sample 11. Code Sample / Example / Snippet of org.apache.storm.topology.BasicOutputCollector | |
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public void shouldEmitSomethingIfTickTupleIsReceived() {
Tuple tickTuple = MockTupleHelpers.mockTickTuple();
BasicOutputCollector collector = mock(BasicOutputCollector.class);
TotalRankingsBolt bolt = new TotalRankingsBolt();
bolt.execute(tickTuple, collector);
verify(collector).emit(any(Values.class));
}
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Like Feedback org.apache.storm.topology.BasicOutputCollector |
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