Java function for arrays like PHP's join()?

I want to join a String[] with a glue string. Is there a function for this?

Solution 1:

Starting from Java8 it is possible to use String.join().

String.join(", ", new String[]{"Hello", "World", "!"})

Generates:

Hello, World, !

Otherwise, Apache Commons Lang has a StringUtils class which has a join function which will join arrays together to make a String.

For example:

StringUtils.join(new String[] {"Hello", "World", "!"}, ", ")

Generates the following String:

Hello, World, !

Solution 2:

If you were looking for what to use in android, it is:

String android.text.TextUtils.join(CharSequence delimiter, Object[] tokens)

for example:

String joined = TextUtils.join(";", MyStringArray);

Solution 3:

In Java 8 you can use

1) Stream API :

String[] a = new String[] {"a", "b", "c"};
String result = Arrays.stream(a).collect(Collectors.joining(", "));

2) new String.join method: https://stackoverflow.com/a/21756398/466677

3) java.util.StringJoiner class: http://docs.oracle.com/javase/8/docs/api/java/util/StringJoiner.html

Solution 4:

You could easily write such a function in about ten lines of code:

String combine(String[] s, String glue)
{
  int k = s.length;
  if ( k == 0 )
  {
    return null;
  }
  StringBuilder out = new StringBuilder();
  out.append( s[0] );
  for ( int x=1; x < k; ++x )
  {
    out.append(glue).append(s[x]);
  }
  return out.toString();
}