使用正则表达式替换字符串

Question

I have a string that I would like to replace using a regular expression in java but I am not quite sure how to do this.

Let's say I have the code below:

String globalID="60DC6285-1E71-4C30-AE36-043B3F7A4CA6";
String regExpr="^([A-Z0-9]{3})[A-Z0-9]*|-([A-Z0-9]{3})[A-Z0-9]*$|-([A-Z0-9]{2})[A-Z0-9]*"

What I would like to do is apply my regExpr in globalID so the new string will be something like : 60D1E4CAE043; I did it with str.substring(0,3)+.... but I was wondering if I can do it using the regexpr in java. I tried to do it by using the replaceAll but the output was not the one I describe above.

To be more specific , I would like to change the globalID to a newglobalID using the regexpr I described above. The newglobalID will be : 60D1E4CAE043.

Thanks

Answer 1

Your regexp must match the whole string . Your wersioe tries to match the parts alternatively which does not work.

thy this:

String regExpr="^([A-Z0-9]{3})[^-]*"+
               "-([A-Z0-9]{2})[^-]*"+
               "-([A-Z0-9]{3})[^-]*"+
               "-([A-Z0-9]{2})[^-]*"+
               "-([A-Z0-9]{2}).*"

Answer 2

This is definitively not the best code ever, but you could do something like this:

String globalID = "60DC6285-1E71-4C30-AE36-043B3F7A4CA6";
String regExpr = "^([A-Z0-9]{3})[A-Z0-9]*|-([A-Z0-9]{3})[A-Z0-9]*$|-([A-Z0-9]{2})[A-Z0-9]*";

Pattern pattern = Pattern.compile(regExpr);
Matcher matcher = pattern.matcher(globalID);
String newGlobalID = "";
while (matcher.find()) {
    for (int i = 1; i <= matcher.groupCount(); i++) {
        newGlobalID += matcher.group(i) != null ? matcher.group(i) : "";
    }
}
System.out.println(newGlobalID);

You will need to use a Matcher to iterate over all matches in your input as your regular expression matches subsequences of the input string only. Depending on which substring is matched a different capturing group will be non-null, you could also use named capturing groups or remember where in the input you currently are, but the above code should work as example.

Answer 3

The total code should be like that below,

String globalID = "60DC6285-1E71-4C30-AE36-043B3F7A4CA6";
    String regExpr = "^(\\w{3}).*?-"
            + "(\\w{2}).*?-"
            + "(\\w{2}).*?-"
            + "(\\w{2}).*?-"
            + "(\\w{3}).*";
    System.out.println(globalID.replaceAll(regExpr, "$1$2$3$4$5"));

The output of println function is

60D1E4CAE043