How to convert String[] (Array) to Collection, like ArrayList or HashSet?
This question is related to
java
arrays
collections
converter
java.util.Arrays.asList(new String[]{"a", "b"})
The easiest way is through
Arrays.asList(stringArray);
Whilst this isn't strictly an answer to this question I think it's useful.
Arrays and Collections can bother be converted to Iterable which can avoid the need for performing a hard conversion.
For instance I wrote this to join lists/arrays of stuff into a string with a seperator
public static <T> String join(Iterable<T> collection, String delimiter) {
Iterator<T> iterator = collection.iterator();
if (!iterator.hasNext())
return "";
StringBuilder builder = new StringBuilder();
T thisVal = iterator.next();
builder.append(thisVal == null? "": thisVal.toString());
while (iterator.hasNext()) {
thisVal = iterator.next();
builder.append(delimiter);
builder.append(thisVal == null? "": thisVal.toString());
}
return builder.toString();
}
Using iterable means you can either feed in an ArrayList or similar aswell as using it with a String...
parameter without having to convert either.
It's a old code, anyway, try it:
import java.util.Arrays;
import java.util.List;
import java.util.ArrayList;
public class StringArrayTest
{
public static void main(String[] args)
{
String[] words = {"word1", "word2", "word3", "word4", "word5"};
List<String> wordList = Arrays.asList(words);
for (String e : wordList)
{
System.out.println(e);
}
}
}
Collections.addAll provides the shortest (one-line) receipt
Having
String[] array = {"foo", "bar", "baz"};
Set<String> set = new HashSet<>();
You can do as below
Collections.addAll(set, array);
String[] w = {"a", "b", "c", "d", "e"};
List<String> wL = Arrays.asList(w);
If you really want to use a set:
String[] strArray = {"foo", "foo", "bar"};
Set<String> mySet = new HashSet<String>(Arrays.asList(strArray));
System.out.println(mySet);
output:
[foo, bar]
The easiest way would be:
String[] myArray = ...;
List<String> strs = Arrays.asList(myArray);
using the handy Arrays utility class. Note, that you can even do
List<String> strs = Arrays.asList("a", "b", "c");
Source: Stackoverflow.com