How to use trim

1

if i ask the user to input 3 integers in one gui box and the integers can be spaced out as much as possible…how would i be able to find each integer and give the sum of the 3 integers using the trim and indexof methods?

2

I think the class “java.util.StringTokenizer” can help to solve your problem.

Regards,

Antony.

3

The below code may help you in solving your problem

/*
	This logic is not only for Three integers. It can work for more than three integers
	USAGE : convert("      0 0 0 0 6 7 9 1  0 0   0   0 0 0  1 2 3 9 5    ");
*/
public static void convert(String str)
{
	int addition  = 0;
	boolean found = false;

	int index = -1;
	int prevIndex = -1;

	for(int i=0; i <= 9; i++)
	{
		index = str.indexOf(i + "");

		if(index != -1 && found)
			index = str.indexOf(i + "",prevIndex);

		if(index != -1)
		{
			addition = addition + i;
			found = true;
			prevIndex = index  + 1;
			i--;
		}
		else
			found=false;
	}

	System.out.println("Addition ------> " + addition);

}
4

Sreekanth,

Your code works, however I can see a problem which will arise - two digit numbers. E.g

String s = “32 m helloworld 3 6”;
convert(s);

Should print out 41, however, the code above only prints 14.

I think the best solution is to use StringTokenizer as Antony has suggested.

5

Martyn,

There are many solutions if we can use the complete Java String API. But the question is to use only “indexOf”. Itz a little bit complicated using only “indexOf, trim()”. Anyway, you have raised a nice question

regards
sreekanth

6

martyn,

package java.util.regex provides efficient way to perform this operation
without using trim() and indexOf(),

import java.util.regex.*;

class addition
{
public static void main(String args[])
{
String str=“32 m helloworld 3 6 “;
Pattern pat=Pattern.compile(”[a-z ]+”);
String array[]=pat.split(str);
int sum=0;
for(int i=0;i<array.length;i++)
{
sum+=Integer.parseInt(array[i]);
}
System.out.println(“sum:”+sum);
}
}

This program prints the correct value:41

7

Hi Noori,

If you were just processing Strings, something like this would remove ALL the whitespaces in a String:

class RemoveWhiteSpacesTest {
public static void main (String args[]) {
String s = “Hello World. This is a TE ST o n l y”;

String a = s.replaceAll(" ", “”);
System.out.println("BEFORE: " + s);
System.out.println("AFTER: " + a);
}
}

Hope that helps.

Martyn

8

Do there have any method like trim to remove the white space?

9

String st = " Fox "
st = st.trim()

very easy!!!

10

Almir,

trim() only removes leading and trailing spaces. My example removes the spaces in between words as well.

Martyn

11

Kalin Ivanov

12

but what if i have to remove white spaces in between in Java.

13

Reshmi,

I posted it above, but here it is again.

class RemoveWhiteSpacesTest {
public static void main (String args[]) {
String s = “Hello World. This is a TE ST o n l y”;

String a = s.replaceAll(" ", “”);
System.out.println("BEFORE: " + s);
System.out.println("AFTER: " + a);
}
}

Hope this helps.

Martyn

14

how do you trim out spaces from a string and and (.+=>< and so on) cheers colin

15

Hi Coco,

A quick and nasty way is to convert the String into a character array with the .toCharArray() method. Once you do that, you can check each character with isLetterOrDigit(char ch) [returns a boolean]. If it is true, then append to a new StringBuffer. If false, just ignore that character.

Ugly, but it should work.

Hope this helps.

Martyn