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Java - different ways of how to iterate over Set or HashSet
14 points
In java we can traverse over Set or HashSet with different ways.
Old ways involve Iterator, with java 8 we can use stream / forEach.
There is also an ancient way with Enumeration.
Below we can see 7 different ways of how to iterate over Set in java.
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import java.util.*;2
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public class JavaIterateOverHashSet {4
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public static void main(String[] args) {6
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Set<String> set = new HashSet<>();8
set.add("A");9
set.add("B");10
set.add("C");11
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System.out.println("#1");13
for (String s : set) {14
System.out.print(s + ", ");15
}16
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System.out.println("\n#2"); // java 818
set.forEach(s -> {19
System.out.print(s + ", ");20
});21
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System.out.println("\n#3"); // java 823
set.forEach(s -> System.out.print(s + ", "));24
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System.out.println("\n#4"); // java 826
set.forEach(System.out::print);27
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System.out.println("\n#5"); // java 829
set.stream().forEach(System.out::print);30
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System.out.println("\n#6");32
Iterator<String> itr = set.iterator();33
while (itr.hasNext()) {34
System.out.print(itr.next() + ", ");35
}36
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System.out.println("\n#7");38
Enumeration elements = new Vector(set).elements();39
while (elements.hasMoreElements()) {40
System.out.print(elements.nextElement() + ", ");41
}42
}43
}Output:
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#12
A, B, C, 3
#24
A, B, C, 5
#36
A, B, C, 7
#48
ABC9
#510
ABC11
#612
A, B, C, 13
#714
A, B, C,