JAVA String Class

The String Class

String objects contain a sequence of characters plus methods that can operate on the string data

The String Class is called with the format:

objectName.methodName(parameters)

Common String Methods

Combine 2 string elements together and print "combine"

String     value1 = "com";

out.println(value1.concat("bine"));

Extract a substring beginning at the 3rd character and is up to but not including the 7th character to print "stop"

The first character in any string is 0 and counts up from there

String     stringSection = "unstoppable".substring(2,6);

out.println(stringSection);

Return a "True" if the string begins with "in"

"inside".startsWith("in");

Return the # of characters contained in a string

"foreverandever".length();

Returns a position of the beginning of a given string inside of another, returns -1 if it is not found

"where's waldo?".indexOf("waldo");

Create a new string with all lower case letters

"I DON'T KNOW".toLowerCase();

Creates a new string with all Upper Case letters

"happy birthday".toUpperCase();

Returns the character at the given position

"project4".charAt(7);

The Character Class

The type char allows you to store a single character

char uses single quotes 'a', '?', '5'

string use double quotes "hello"

Methods like charAt return a char type output

char     numberPeople = "5 guests".charAt(0);

Each character that can be expressed with a char type also has a number assigned to it called  ASCII/UTF-16 values

'A'  is 65

'B' is 66

'a' is 97

'b' is 98

'*' is 42

Common Character Methods