java编程思想-第13章-某些练习题

. 匹配任意一个字符

* 表示匹配0个或多个前面这个字符

+ 表示1个或多个前面这个字符

? 表示0个或1个前面这个字符

^ 表示一行的开始 　　^[a-zA-Z] ：表示开头是a-z或者A-Z

　　[^0-9] ：表示不是数字，除数字以外的

$ 表示一行的结束

\w 表示词字符[a-zA-Z0-9]

\W 表示非词字符[^\w]

第七题:

  package net.mindview.strings.test7;

public class Test7 {

    public static void main(String[] args) {
        //两种写法都可以
        String regex = "^[A-Z].*\\.$";//"^[A-Z].*\\."这样也对
        String regex1 = "\\p{Upper}.*\\.$";
        String str = "D.";
        String str1 = "Dfasdfasfasfdasfdasfasfasdf.";
        String str2 = "Dfasdfasfasfdasfdasfasfasdf.E";
        System.out.println(str.matches(regex));
        System.out.println(str1.matches(regex));
        System.out.println(str2.matches(regex));
        System.out.println(str.matches(regex1));
        System.out.println(str1.matches(regex1));
        System.out.println(str2.matches(regex1));
    }
}

运行结果:

  true

true
false
true
true
false

第八题

package net.mindview.strings;

import java.util.Arrays;

public class Splitting {

    public static String knights = "Then, when you have found the shrubbery, you must cut down the mightiest tree in the forest... with... a herring!";

    public static void split(String regex){
        System.out.println(Arrays.toString(knights.split(regex)));
    }
    public static void main(String[] args) {
        //表示的时按照空格分割字符串
        //运行结果:[Then,, when, you, have, found, the, shrubbery,, you, must, cut, down, the, mightiest, tree, in, the, forest..., with..., a, herring!]
        split(" ");

        //表示按照非单次字符分割字符串--这里的非单次字符是空格和,
        //运行结果:[Then, when, you, have, found, the, shrubbery, you, must, cut, down, the, mightiest, tree, in, the, forest, with, a, herring]
        split("\\W+");
        //这个表示:费单次字符之前带n的地方进行分割字符串 这里的分割符是n空格和n,
        //运行结果:[The, whe, you have found the shrubbery, you must cut dow, the mightiest tree i, the forest... with... a herring!]
        split("n\\W+");
    }

}

package net.mindview.strings.test8;

import net.mindview.strings.Splitting;

public class Test8 {

    public static void main(String[] args) {
        String regex = "the|you";
        Splitting.split(regex);
    }
}

第九题

package net.mindview.strings.test9;

import net.mindview.strings.Splitting;

public class Test9 {
    public static void main(String[] args) {
        String regex = "A|E|I|O|U|a|e|i|o|u";
        //通过嵌入式标志表达式  (?i) 也可以启用不区分大小写的匹配。
        String regex1 = "(?i)a|e|i|o|u";
        //[abc] 表示a或b或c
        String regex2 = "(?i)[aeiou]";
        System.out.println(Splitting.knights.replaceAll(regex, "_"));
        System.out.println(Splitting.knights.replaceAll(regex1, "_"));
        System.out.println(Splitting.knights.replaceAll(regex2, "_"));
    }
}