- String Methods operate on Java Strings. They can be used to find the length of the string, convert to lowercase, etc.
- Some of the commonly used String methods are:
String name = “Kishan”;
- (Indexes of the above string are as follows: 0-K, 1-i, 2-s, 3-h, 4-a, 5-n)
| Methods | Description |
|---|---|
| 1. length() | Returns the length of String name. (6 in this case) |
| 2. toLowerCase() | Converts all the characters of the string to the lower case letters. |
| 3. toUpperCase() | Converts all the characters of the string to the upper case letters. |
| 4. trim() | Returns a new String after removing all the leading and trailing spaces from the original string. |
| 5. substring(int start) | Returns a substring from start to the end. Substring(3) returns “han”. [Note that indexing starts from 0] |
| 6. substring(int start, int end) | Returns a substring from the start index to the end index. The start index is included, and the end is excluded. |
| 7. replace(‘K’, ‘p’) | Returns a new string after replacing K with p. pishan is returned in this case. (This method takes char as argument) |
| 8. startsWith(“Ki”) | Returns true if the name starts with the string “Ki”. (True in this case) |
| 9. endsWith(“an”) | Returns true if the name ends with the string “an”. (True in this case) |
| 10. charAt(2) | Returns the character at a given index position. (s in this case) |
| 11. indexOf(“s”) | Returns the index of the first occurrence of the specified character in the given string. |
| 12. lastIndexOf(“h”) | Returns the last index of the specified character from the given string. (3 in this case) |
| 13. equals(“Kishan”) | Returns true if the given string is equal to “Kishan” false otherwise [Case sensitive] |
| 14.equalsIgnoreCase(“kishan”) | Returns true if two strings are equal, ignoring the case of characters. |
- The sequence of characters after backslash ‘\’ = Escape Sequence Characters
- Escape Sequence Characters consist of more than one character but represent one character when used within the strings.
- Examples: \n (newline), \t (tab), \’ (single quote), \ (backslash), etc.
public class cwh_14_string_methods {
public static void main(String[] args) {
String name = "Kishan";
System.out.println(name);
int value = name.length();
System.out.println(value);
String lstring = name.toLowerCase();
System.out.println(lstring);
String ustring = name.toUpperCase();
System.out.println(ustring);
String nonTrimmedString = " Kishan ";
System.out.println(nonTrimmedString);
String trimmedString = nonTrimmedString.trim();
System.out.println(trimmedString);
System.out.println(name.substring(1));
System.out.println(name.substring(1,5));
System.out.println(name.replace('K', 'p'));
System.out.println(name.replace("n", "ier"));
System.out.println(name.startsWith("Kis"));
System.out.println(name.endsWith("dd"));
System.out.println(name.charAt(4));
String modifiedName = "Harryrryrry";
System.out.println(modifiedName.indexOf("rry"));
System.out.println(modifiedName.indexOf("rry", 4));
System.out.println(modifiedName.lastIndexOf("rry", 7));
System.out.println(name.equals("Kishan"));
System.out.println(name.equalsIgnoreCase("KiShAn"));
System.out.println("I am escape sequence\tdouble quote");
}
}