String類很常用,很重要。
String不像int或float, 它是參考類型。final類型, 不能被繼承,String is a Reference Type,Defined in java.lang package
馬克- to-win:馬克 java社區:防盜版實名手機尾號: 73203。
常用方法:
length()
String greeting = “Hello”;
int n = greeting.length();//is 5
charAt(n)(取某個位置字符)
char first = greeting.charAt(0);
char last = greeting.charAt(4);
substring()(取子字符串)
String s = greeting.substring(0,3);//from 0 inclusive to 3 exclusive
Concatenation(鏈接)
String a = greeting + “ world!”+ 2009;
Equality(don’t use ==)(測試是否相等)
String s = “Hello”; s.equals(greeting);
“Hello”.equalsIgnoreCase(“hello”);(忽略大小寫的測試相等)
本章源碼
例子:
public class Test {
public static void main(String args[]) {
String letters = “abcdefghijklabcdefghijkl”;
/*這裡講講閱讀源代碼,control點擊進入方法*/
System.out.println(“‘c’在第” + letters.indexOf(‘c’) + “個”);
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