CODEWITHSUNDEEP
javaregex
Ricardo
Ricardo

Reputation: 21

Java regular expression

I have the following string "product-code" and I want to convert it to "productCode" using regular expression.

I think that te logic is very simple, I just need to replace the '-' char for the next converted to upper case.

But I don't know how to do that... can anybody help me?

Thanks a lot.

Upvotes: 2

Views: 443

Answers (5)

tnunamak
tnunamak

Reputation: 2069

No need to over-complicate it...

  String p = "product-code";
  String[] values = p.split("-");
  char[] letters = values[1].toCharArray();
  letters[0] =Character.toUpperCase(letters[0]);
  System.out.println(values[0]+String.copyValueOf(letters));

Upvotes: 1

Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 299218

Here is a variation loosely based on Jason S' solution (meaning that I started out with his code and then changed it to suit my needs). The clue is that Guava has a class that does exactly this conversion, the CaseFormat class (or enum, to be more precise). So what I did was search for lower case words with dashes and feed them to the CaseFormat converter. (Converting from LOWER_HYPHEN to LOWER_CAMEL)

public class CamelizeDashes {

    private static final Pattern WORD_WITH_DASHES =
        Pattern.compile("\\b(\\p{Lower}+(?:\\-\\p{Lower}+)+)\\b");

    private static String camelizeDashes(final String input) {
        final StringBuffer sb = new StringBuffer();
        final Matcher m = WORD_WITH_DASHES.matcher(input);
        while (m.find())
        {
            System.out.println("Match found: "+m.group());
            m.appendReplacement(sb, toCamelCase( m.group()));
        }
        m.appendTail(sb);
        return sb.toString();
    }
    public static void main(final String[] args)
    {
        test("Sed laoreet-neque-at libero luctus ultricies. Duis nulla justo, " +
            "tempor-nec viverra ut, convallis a diam. Praesent eget-nunc-sed " +
        "eros interdum sodales tempus-nec metus.");

    }
    private static void test(final String input) {
        System.out.println(camelizeDashes(input));
    }
    private static String toCamelCase(final String dashedword) {
        return CaseFormat.LOWER_HYPHEN.to(CaseFormat.LOWER_CAMEL, dashedword);
    }
}

Output:

Match found: laoreet-neque-at
Match found: tempor-nec
Match found: eget-nunc-sed
Match found: tempus-nec
Sed laoreetNequeAt libero luctus ultricies. Duis nulla justo, temporNec viverra ut, convallis a diam. Praesent egetNuncSed eros interdum sodales tempusNec metus.

Upvotes: 0

Brian Clapper
Brian Clapper

Reputation: 26230

This isn't as complicated as it seems. Using Pattern, Matcher and a few regular expression groups, it's just a few lines of code:

Pattern re = Pattern.compile("^([^-]+)-(.)(.*)$");
Matcher m = re.matcher("product-code");
if (m.matches())
{
    // Could do: s = m.group(1) + m.group(2).toUpperCase() + m.group(3)
    // Using a StringBuilder is more efficient, though.
    StringBuilder buf = new StringBuilder();
    buf.append(m.group(1));
    buf.append(m.group(2).toUpperCase());
    buf.append(m.group(3));
    System.out.println(buf.toString());
}

Turning this into a general function or method is left as an exercise to the reader. ;-)

EDIT

Handling multiple matches:

String s = "product-code boo-yah";
Pattern re = Pattern.compile("^([^-]+)-(.)(.*)$");
Matcher m = re.matcher(s);
while (m.matches())
{
    s = m.group(1) + m.group(2).toUpperCase() + m.group(3);
    m = re.matcher(s);
}

System.out.println(s);

NOTE: I did test that code.

Upvotes: 2

Gato3
Gato3

Reputation: 49

Regular expressions are for searching strings, not for replacing them. Just write simple java code like this:

public static String convert(String text) {
    StringBuilder resp = new StringBuilder(text.length());
    boolean upper = false;
    for (int i = 0; i < text.length(); i++) {
        char ch = text.charAt(i);
        if (ch == '-') {
            upper = true;
        } else {
            if (upper) {
              ch = Character.toUpperCase(ch);
              upper = false;
            }
            resp.append(ch);
        }
    }
    return resp.toString();
}

Upvotes: 1

Jason S
Jason S

Reputation: 189916

Try using appendReplacement and appendTail -- they are very flexible and let you use arbitrary procedures for replacing fragments of strings.

package com.example.test;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class CapitalizeDash {
    static public void main(String[] args)
    {
        test("ha----");
        test("onions");
        test("product-code");
        test("this-is-a-test");

    }

    // this matches a dash followed by any non-dash
    private static Pattern p = Pattern.compile("-([^-])");
    private static void test(String input) {
        System.out.println(capitalizeDash(input));
    }
    private static String capitalizeDash(String input) {
        StringBuffer sb = new StringBuffer();
        Matcher m = p.matcher(input);
        while (m.find())
        {
            m.appendReplacement(sb, m.group(1).toUpperCase());          
        }
        m.appendTail(sb);
        return sb.toString();       
    }
}

Upvotes: 4

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