Strings and Things - Java - page 83

Taking Strings Apart with Substrings

Problem

You want to break a string apart into substrings by position.

Solution

Use the String object's substring() method.

Discussion

The substring() method constructs a new String object made up of a run of characters
contained somewhere in the original string, the one whose substring() you called. The
substring method is overloaded: both forms require a starting index (which is always zero-
based ). The one-argument form returns from startIndex to the end. The two-argument
form takes an ending index (not a length, as in some languages), so that an index can be gen-
erated by the String methods indexOf() or lastIndexOf() .

WARNING

Note that the end index is one beyond the last character! Java adopts this “half open inter-
val” (or inclusive start, exclusive end) policy fairly consistently; there are good practical
reasons for adopting this approach, and some other languages do likewise.

public public class class SubStringDemo SubStringDemo {

public public static void main ( String [] av ) {

String a = "Java is great." ;
System . out . println ( a );
String b = a . substring ( 5 );

static void

// b is the String "is great."

System . out . println ( b );
String c = a . substring ( 5 , 7 ); // c is the String "is"
System . out . println ( c );
String d = a . substring ( 5 , a . length ()); // d is "is great."
System . out . println ( d );

}

}