List<String> list = ..;
String[] array = list.toArray(new String[0]);
For example:
List<String> list = new ArrayList<String>();
//add some stuff
list.add("android");
list.add("apple");
String[] stringArray = list.toArray(new String[0]);
The toArray() method without passing any argument returns Object[]. So you have to pass an array as an argument, which will be filled with the data from the list, and returned. You can pass an empty array as well, but you can also pass an array with the desired size.
Important update: Originally the code above used new String[list.size()]. However, this blogpost reveals that due to JVM optimizations, using new String[0] is better now.
List<String> list = ..;
String[] array = list.toArray(new String[0]);
For example:
List<String> list = new ArrayList<String>();
//add some stuff
list.add("android");
list.add("apple");
String[] stringArray = list.toArray(new String[0]);
The toArray() method without passing any argument returns Object[]. So you have to pass an array as an argument, which will be filled with the data from the list, and returned. You can pass an empty array as well, but you can also pass an array with the desired size.
Important update: Originally the code above used new String[list.size()]. However, this blogpost reveals that due to JVM optimizations, using new String[0] is better now.
An alternative in Java 8:
String[] strings = list.stream().toArray(String[]::new);
Java 11+:
String[] strings = list.toArray(String[]::new);
In Java 8 or later:
String listString = String.join(", ", list);
In case the list is not of type String, a joining collector can be used:
String listString = list.stream().map(Object::toString)
.collect(Collectors.joining(", "));
If you happen to be doing this on Android, there is a nice utility for this called TextUtils which has a .join(String delimiter, Iterable) method.
List<String> list = new ArrayList<String>();
list.add("Item 1");
list.add("Item 2");
String joined = TextUtils.join(", ", list);
Obviously not much use outside of Android, but figured I'd add it to this thread...
Use like this.
List<String> stockList = new ArrayList<String>();
stockList.add("stock1");
stockList.add("stock2");
String[] stockArr = new String[stockList.size()];
stockArr = stockList.toArray(stockArr);
for(String s : stockArr)
System.out.println(s);
Try this
String[] arr = list.toArray(new String[list.size()]);
String [] countriesArray = countryList.toArray(new String[countryList.size()]);
I have assumed that your country List name is countryList.
So to convert ArrayList of any class into array use following code. Convert T into the class whose arrays you want to create.
List<T> list = new ArrayList<T>();
T [] countries = list.toArray(new T[list.size()]);
Please help me to convert ArrayList to String[], ArrayList Contains Values Object(VO) as Values.
As you mentioned that list contains Values Object i.e. your own class you need toString() overridden to make this work correctly.
This code works. Assuming VO is your Value Object class.
List<VO> listOfValueObject = new ArrayList<VO>();
listOfValueObject.add(new VO());
String[] result = new String[listOfValueObject.size()];
for (int i = 0; i < listOfValueObject.size(); i++) {
result[i] = listOfValueObject.get(i).toString();
}
Arrays.sort(result);
List<String> sortedList = Arrays.asList(result);
The snippet of
List<VO> listOfValueObject = new ArrayList<VO>();
listOfValueObject.add(new VO());
String[] countriesArray = listOfValueObject.toArray(new String[listOfValueObject.size()]);
will give you ArrayStoreException due VO is not the String type as required by native method arraycopy subsequently called from toArray one.