Java Strings in 10 minutes

Declaring/creating a new String String strName = ""; String str = "WLCS"; String str2 = "Hello"; //String is the type name

Size/length of a string String str = "WLCS"; System.out.println( str.length() ); //returns 4

String Library of Methods Strings have many pre-made methods in Java Examples length() equals() substring() Etc. Java String Library

Comparing if Strings are equal == does NOT work Must use the .equals() method str2.equals("Hello"); //returns true strName.equals(str2); //return false

Substrings (Strings slices) strName.substring(a,b) Returns a substring from index a up to b (exclusive) String str = "Hello, world"; System.out.println( str.substring(0,5) ); //returns Hello System.out.println( str.substring(7, str.length()) ); //returns World

Searching for a substring strName.indexOf(String substr) returns the index of the specific substr String str = "Hello, world"; System.out.println( str.indexOf(",") ); //returns 5 System.out.println( str.indexOf("wo") ); //returns 7 System.out.println( str.indexOf("qwerty") ); //returns -1

Comparing Strings alphabetically strName.compareTo(String str) returns an integer indicating alphabetical order String str1 = "abc"; String str2 = "def"; System.out.println(str1.compareTo(str2)); //returns -3 System.out.println(str1.compareTo(str1)); //returns 0 System.out.println(str2.compareTo(str1)); //returns 3

compareTo() example String str1 = "abc"; String str2 = "def"; if (str1.compareTo(str2) < 0) { System.out.println(str1 + " goes before " + str2); }

Other useful String methods toLowerCase() toUpperCase() trim() split()