One long section of code outlining how to achieve some basic string handling objectives in Java. Currently trying to get to grips with this language after spending far too many years concentrating on C++. Each technique is demonstrated with a code snippet. As with a lot of my other stuff, any new stuff I find useful will get added at a later date:
package stringdemos; import java.util.*; public class StringDemos { public static void main(String[] args) { // Initialize string String greeting = "Hello world!"; System.out.println( greeting ); // String length int len = greeting.length(); // Copy string into temporary character array char[] tempCharArray = new char[len]; for (int i = 0; i < len; i++) { tempCharArray[i] = greeting.charAt(i); } // Reverse an array of chars for (int j = 0; j < len / 2; j++) { char temp = tempCharArray[ j ]; tempCharArray[ j ] = tempCharArray[ len - j - 1 ]; tempCharArray[ len - j - 1 ] = temp; } System.out.println( tempCharArray ); // Concatenate strings String strCat = greeting.concat( " "); strCat = strCat + "Again"; // Output formatting double v = 1.234; String fs = String.format( "\nValue = %.2f", v ); System.out.println( fs ); // Convert number to string and vice versa Float fv = Float.valueOf( "1.23"); String fvStr = String.valueOf(( fv )); // Getting substrings String sub1 = greeting.substring( 0, 4 ); String sub2 = greeting.substring( 4 ); // Tokenizing strings eg whitespaces String[] tok = greeting.split(" "); // Remove any trailing and leading whitespaces String whiteSpace = " remove white spaces, beginning and end "; whiteSpace.trim(); // Convert upper/lower cases String strCase = greeting.toLowerCase(); strCase = strCase.toUpperCase(); // Find characters and substrings in strings String txt1 = "Hello"; String txt2 = "Hello"; String txt3 = "hello"; int comp = txt1.compareTo(txt2); comp = txt1.compareTo(txt3); comp = txt1.compareToIgnoreCase(txt3); // Finding substrings within strings String strFind = "The cat sat on the mat"; int index1 = strFind.indexOf("at"); // First occurence int index2 = strFind.indexOf("at", index1 + 1); // Next occurence int index3 = strFind.indexOf("at", index2 + 1); // Next occurence // Sorting string arrays String[] txt = { "I", "walk", "the", "line" }; List<String> list = Arrays.asList(txt); Collections.sort(list); System.out.println(list); } }