CODEWITHSUNDEEP
javaregex
squiroid
squiroid

Reputation: 14027

Convert middle substring to "*"

I have a string String email="[email protected]" so its length is 24.

I want result like rachit************il.com.That means 1/4 of initial same and last 1/4 same.

Just want to convert 1/2 from middle to * with the help of regEX.

Thanks

Upvotes: 0

Views: 68

Answers (3)

JuniorCompressor
JuniorCompressor

Reputation: 20025

You could convert to char array, process and convert back to String:

String email = "[email protected]";
char[] a = email.toCharArray();
for (int i = 0, j = a.length >> 2; i < a.length >> 1; i++, j++)
    a[j] = '*';
email = new String(a);

Result:

rachit************il.com

You can't identify the middle of a string using a single regular expression unless the lengths have a finite number of values.

Upvotes: 1

PeterK
PeterK

Reputation: 1723

You could do something like this: 

"[email protected]".replaceAll("(?<=.{5}).(?=.{5})", "*");

this will replace all characters to * apart from the first and last 5.

In response to your question, you could make this flexible like this:

String email = "[email protected]";
int i = email.length() / 4;
email = email.replaceAll("(?<=.{" + i + "}).(?=.{" + i + "})", "*");

Just a word of warning, if you were to start using this in production code, you probably want to create a way of caching these regexes, based on the value of i. This way is for demonstration of the pattern only, and will compile a regex Pattern each time it is used.

Upvotes: 2

Mshnik
Mshnik

Reputation: 7032

One way to do it is to create a string of '*'s that is the correct length, then concatenate on the surrounding parts of the original string. That way you don't have to do any looping:

public static String starize(String str){
    char[] middle = new char[str.length()/2];
    Arrays.fill(middle, '*');
    return str.substring(0, str.length()/4) 
           + String.copyValueOf(middle) 
           + str.substring(3 * str.length() / 4);
}

Upvotes: 1

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