How do I remove substring from StringBuilder?

By Wayan in Core API, Lang Package 0 Comment

This example demonstrate you how to use the StringBuilder delete(int start, int end) and deleteCharAt(int index) to remove a substring or a single character from a StringBuilder.

package org.kodejava.lang;

public class StringBuilderDelete {
    public static void main(String[] args) {
        StringBuilder lipsum = new StringBuilder("Lorem ipsum dolor sit " +
                "amet, consectetur adipisicing elit.");
        System.out.println("lipsum = " + lipsum);

        // We'll remove a substring from this StringBuilder starting from
        // the first character to the 28th character.
        lipsum.delete(0, 28);
        System.out.println("lipsum = " + lipsum);

        // Removes a char from the StringBuilder. In the example below we
        // remove the last character.
        lipsum.deleteCharAt(lipsum.length() - 1);
        System.out.println("lipsum = " + lipsum);
    }
}

The result of the code snippet above:

lipsum = Lorem ipsum dolor sit amet, consectetur adipisicing elit.
lipsum = consectetur adipisicing elit.
lipsum = consectetur adipisicing elit

How do I reverse a string by word?

By Wayan in Core API, Util Package 0 Comment

In the other examples on this website you might have seen how to reverse a string using StringBuffer, StringUtils from Apache Commons Lang library or using the CharacterIterator.

In this example you’ll see another way that you can use to reverse a string by word. Here we use the StringTokenizer and the Stack class.

package org.kodejava.util;

import java.util.Stack;
import java.util.StringTokenizer;

public class ReverseStringByWord {
    public static void main(String[] args) {
        // The string that we'll reverse
        String text = "Jackdaws love my big sphinx of quartz";

        // We use StringTokenize to get each word of the string. You might try
        // to use the String.split() method if you want.
        StringTokenizer st = new StringTokenizer(text, " ");

        // To reverse it we can use the Stack class, which implements the LIFO
        // (last-in-first-out).
        Stack<String> stack = new Stack<>();
        while (st.hasMoreTokens()) {
            stack.push(st.nextToken());
        }

        // Print each word in reverse order
        while (!stack.isEmpty()) {
            System.out.print(stack.pop() + " ");
        }
    }
}

How do I remove trailing white space from a string?

By Wayan in Core API, Lang Package 0 Comment

The trim() method of a String class removes both leading and trailing white space from a string. In this example we use a regular expression to remove only the trailing white spaces from a string.

package org.kodejava.lang;

public class TrailingSpace {
    public static void main(String[] args) {
        String text = "     tattarrattat     ";
        System.out.println("Original      = " + text);
        System.out.println("text.length() = " + text.length());

        // Using a regular expression to remove only the trailing white space in
        // a string
        text = text.replaceAll("\\s+$", "");
        System.out.println("Result        = " + text);
        System.out.println("text.length() = " + text.length());
    }
}

Original      =      tattarrattat     
text.length() = 22
Result        =      tattarrattat
text.length() = 17

How do I remove leading white space from a string?

By Wayan in Core API, Lang Package 0 Comment

The trim() method of a String class removes both leading and trailing white space from a string. In this example we use a regular expression to remove only the leading white spaces from a string.

package org.kodejava.lang;

public class LeadingSpace {
    public static void main(String[] args) {
        String text = "     tattarrattat     ";
        System.out.println("Original      = " + text);
        System.out.println("text.length() = " + text.length());

        // Using regular expression to remove only the leading white
        // space in string
        text = text.replaceAll("^\\s+", "");
        System.out.println("Result        = " + text);
        System.out.println("text.length() = " + text.length());
    }
}

Original      =      tattarrattat     
text.length() = 22
Result        = tattarrattat     
text.length() = 17

How do I replace characters in string?

By Wayan in Core API, Lang Package 0 Comment 
package org.kodejava.lang;

public class StringReplace {
    public static void main(String[] args) {
        String text = "The quick brown fox jumps over the lazy dog";
        System.out.println("Before: " + text);

        // The replace method replace all occurrences of character
        // 'o' with 'u' and returns a new string object.
        text = text.replace('o', 'u');
        System.out.println("After : " + text);
    }
}

The result of the code snippet:

Before: The quick brown fox jumps over the lazy dog
After : The quick bruwn fux jumps uver the lazy dug