80 lines
2.3 KiB
Java
80 lines
2.3 KiB
Java
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Simple Strings
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/**
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* messing about with Java Strings
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*/
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public class SimpleStrings {
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public static void main( String[] args ) {
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// a string is a array of characters
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char[] helloChars = {'h', 'e', 'l', 'l', 'o'};
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String helloString = new String( helloChars );
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System.out.println( helloString );
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// best way to assign a string literal
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helloString = "hello";
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// no need to do this
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helloString = new String( "hello" );
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// an example
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String barryWhite = "i love you all!";
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System.out.println( barryWhite.length() ); // 15
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System.out.println( barryWhite.charAt( 0 ) ); // i
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System.out.println( barryWhite.startsWith( "i love" ) ); // true
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System.out.println( barryWhite.endsWith( "all" ) ); // false
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System.out.println( barryWhite.indexOf( 'l' ) ); // 2
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System.out.println( barryWhite.indexOf( "you" ) ); // 7
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System.out.println( barryWhite.substring( 7 ) ); // you all!
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System.out.println( barryWhite.substring( 3, 8 ) ); // ove y
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// String equality
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String a = "hello";
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String b = "world";
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String c = new String( "hello" );
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String d = a;
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// == between Java objects is on reference equality
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// equals() method is used to value equality
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System.out.println( a == b ); // false
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System.out.println( a == c ); // false
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System.out.println( a.equals( c ) ); // true
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System.out.println( a == d ); // true
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// String are immutable
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String noChange = "have i changed, not likely";
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noChange.substring( 3 );
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noChange.toLowerCase();
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noChange.toUpperCase();
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noChange.trim();
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System.out.println( noChange ); // have i changed, not likely
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// StringBuffer usage
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StringBuffer buffer = new StringBuffer();
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for( int i = 0; i < 10; i++ ) {
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buffer.append( "say hello: " );
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buffer.append( i );
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buffer.append( "\n" );
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}
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System.out.println( buffer );
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/**
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* this outputs
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* say hello: 0
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* say hello: 1
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* say hello: 2
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* say hello: 3
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* say hello: 4
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* say hello: 5
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* say hello: 6
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* say hello: 7
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* say hello: 8
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* say hello: 9
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*/
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}
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}
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