Java Reference
In-Depth Information
Use the
substring()
method to obtain a portion of the string between two different
positions. In the solution that follows, a string is created and then various portions of
the string are printed out using the
substring()
method.
public static void substringExample(){
String originalString = "This is the original String";
System.out.println(originalString.substring(0,
originalString.length()));
System.out.println(originalString.substring(5,
20));
System.out.println(originalString.substring(12));
}
Running this method would yield the following results:
This is the original String
is the original
original String
How It Works
The
String
object contains many helper methods. One such method is
sub-
string()
, which can be used to obtain portions of the string. There are two vari-
ations of the
substring()
method. One of them accepts a single argument, that be-
ing the starting index; and the other accepts two arguments:
startingindex
and
endingindex
. Having two variations of the
substring()
method makes it seem
as though the second argument is optional; if it is not specified, the length of the calling
string is used in its place. It should be noted that indices begin with zero, so the first
position in a string has the index of 0, and so on.
As you can see from the solution to this recipe, the first use of
substring()
prints out the entire contents of the string. This is because the first argument passed to
the
substring()
method is 0, and the second argument passed is the length of the
original string. In the second example of
substring()
, an index of 5 is used as the
first argument, and an index of 20 is used as the second argument. This effectively
causes only a portion of the string to be printed, beginning with the character in the
string that is located in the sixth position, or index 5 because the first position has an
index of 0; and ending with the character in the string that is located in the 20th posi-
