concat(), replace(), and trim() Strings in Java
By: Ivan Lim
concat()
You can concatenate two strings using concat(), shown here:
String concat(String str)
This method creates a new object that contains the invoking string with the contents of str appended to the end. concat( ) performs the same function as +. For example,
String s1 = "one";
String s2 = s1.concat("two");
puts the string "onetwo" into s2. It generates the same result as the following sequence:
String s1 = "one";
String s2 = s1 + "two";
replace()
The replace( ) method replaces all occurrences of one character in the invoking string with another character. It has the following general form:
String replace(char original, char replacement)
Here, original specifies the character to be replaced by the character specified by replacement. The resulting string is returned. For example,
String s = "Hello".replace('l', 'w');
puts the string "Hewwo" into s.
trim()
The trim( ) method returns a copy of the invoking string from which any leading and trailing whitespace has been removed. It has this general form:
String trim( )
Here is an example:
String s = " Hello World ".trim();
This puts the string "Hello World" into s.
The trim( ) method is quite useful when you process user commands. For example, the following program prompts the user for the name of a state and then displays that state's capital. It uses trim( ) to remove any leading or trailing whitespace that may have inadvertently been entered by the user.
// Using trim() to process commands.
import java.io.*;
class UseTrim {
public static void main(String args[])
throws IOException
{
// create a BufferedReader using System.in
BufferedReader br = new
BufferedReader(new InputStreamReader(System.in));
String str;
System.out.println("Enter 'stop' to quit.");
System.out.println("Enter State: ");
do {
str = br.readLine();
str = str.trim(); // remove whitespace
if(str.equals("Illinois"))
System.out.println("Capital is Springfield.");
else if(str.equals("Missouri"))
System.out.println("Capital is Jefferson City.");
else if(str.equals("California"))
System.out.println("Capital is Sacramento.");
else if(str.equals("Washington"))
System.out.println("Capital is Olympia.");
// ...
} while(!str.equals("stop"));
}
}
Archived Comments
1. JasonNix
View Tutorial By: JasonNix at 2017-04-25 08:36:35
2. JasonNix
View Tutorial By: JasonNix at 2017-04-13 02:27:07
3. can apply this code in android
View Tutorial By: Tech Genus at 2016-05-05 11:29:57
4. how to trim in jsp page and to send the trimed conten to servlet?
View Tutorial By: monishaa at 2015-07-16 10:06:11
5. Can I ask something,
Can you show me how to use TRIM in GUI
TQ =)
View Tutorial By: wawa at 2014-05-03 15:28:35
6. one of the best example for trim()....
View Tutorial By: sharad at 2013-01-29 13:43:58
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