Java正则表达式

// 1. String start with alpha word and then followed by
//    any aplha or number. e.g. Abc 20 Jan to 15 Dec

// One or more alpha-characters, followed by a space,
//     followed by some alpha-numeric character, followed by what ever
Pattern p = Pattern.compile("\\p{Alpha}+ \\p{Alnum}.*");
for (String s : new String[] {"Abc 20 Jan to 15 Dec", "hello world", "123 abc"})
    System.out.println(s + " matches: " + p.matcher(s).matches());

// 2. String for a decimal number. e.g. 450,122,224.00
p = Pattern.compile(
        "\\p{Digit}+(\\.\\p{Digit})?|" +  // w/o thousand seps.
        "\\p{Digit}{1,3}(,\\p{Digit}{3})*\\.\\p{Digit}+"); // w/ thousand seps.
for (String s : new String[] { "450", "122", "224.00", "450,122,224.00", "0.0.3" })
    System.out.println(s + " matches: " + p.matcher(s).matches());


// 3. Also to check if String contain any pattern like 'Page 2 of 20'

// "Page" followed by one or more digits, followed by "of"
// followed by one or more digits.
p = Pattern.compile("Page \\p{Digit}+ of \\p{Digit}+");
for (String s : new String[] {"Page 2 of 20", "Page 2 of X"})
    System.out.println(s + " matches: " + p.matcher(s).matches());

输出:

Abc 20 Jan to 15 Dec matches: true
hello world matches: true
123 abc matches: false
450 matches: true
122 matches: true
224.00 matches: true
450,122,224.00 matches: true
0.0.3 matches: false
Page 2 of 20 matches: true
Page 2 of X matches: false

1.) /[A-Z][a-z]*(\s([\d]+)|\s([A-Za-z]+))+/

[A-Z][a-z]* 大写的

\s([\d]+)

\s([A-Za-z]+) 作为一个单词的前缀应该是一个空格

2.) /(\d{1,3})(,(\d{3}))*(.(\d{2}))/

(\d{1,3})

(,(\d{3}))* 以逗号为前缀的0或更多三位数的数字

(.(\d{2})) 是两位数的小数

3.) /Page (\d+) of (\d+)/

(\d+) 一个或多个数字

写这个(或任何正则表达式)时,我喜欢使用 this tool

我不知道你在这里是什么意思。开头是一个单词,后面是任意数量的单词和数字? 试试这个:

^[a-zA-Z]+(\s+([a-zA-Z]+|\d+))+

只要一个十进制数就可以了

\d+(\.\d+)?

\d{1,3}(,\d{3})*(\.\d+)?

三 使用

Page \d+ of \d+