Topic |
Notes |
String Class |
- The String object is immutable. Which means once the String object it is created,
it cannot be changed.
- When you add two String objects together, a third object is created.
- String objects can be created by using the "new" keyword or by using a
literal. Example:
1. String strTest = new String("Hello")
2. String strTest = "Hello"
Note: The StringBuffer object allows strings to be concatenated without creating a new
object. |
length() |
Gives the number of
chars in a string. Example
- System.out.println( "Hello".length() ); - shows 5
- String T = new String("Hello");
System.out.println( T.length() ); - shows 5
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substring() |
- substring(begin, end*); - warning, returns the
begining char (index starts with 0) through (end - 1).
Examples
- "hello".substring(1,2) - returns "e"
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toUpperCase() |
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toLowerCase() |
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String.equals() vs
StringBuffer.equals() |
- String's equals() is overridden to give you equality of the contents of the object.
- StringBuffer's equals just checks for equality of the object references. Note:
Object's equals() is not overridden.
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equalsIgnoreCase() |
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charAT() |
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concat() |
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indexOf() |
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lastIndexOf() |
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toString() |
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trim() |
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