android - 从字符串中提取 4 位数字的正则表达式 - Android

Question

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Answer 1

String data = "Your otp for the login is 7832. This code will expire at 12:43:09PM";

Pattern pattern = Pattern.compile("(\\d{4})");

//   \d is for a digit 
//   {} is the number of digits here 4.

Matcher matcher = pattern.matcher(data);
String val = "";
if (matcher.find()) {        
    val = matcher.group(0);  // 4 digit number
}