3、正则demo之替换

String类的replaceAll(string str, regex reg)

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1.将数字替换为"#"

String str = "sdfasdf123456wdfgfdy39534056546f";
String reg = "\\d";
str = str.replaceAll(reg,"#");

2.将叠词替换为&

String str1 = "erkktyqqquizzzzzo";
String reg1="(.)\\1+";
str1=str1.replaceAll(reg,"&");

3.将重叠的字母替换为单个的字母,$表示获取一个组，$1表示获取前一个规则中的第一个组

String str1 = "erkktyqqquizzzzzo";
String reg1="(.)\\1+";
str1=str1.replaceAll(reg,"$1");