Search given string array and replace with another string array using Regex

Question

Hi All,
I want to search the given string array and replace with another string array using regex in java
for example,
String news = "If you wish to search for any of these characters, they must be preceded by the character to be interpreted"
String fromValue[] = {"you", "search", "for", "any"}
String toValue[] = {"me", "dont search", "never", "trip"}
so the string "you" needs to be converted to "me" i.e you --> me. Similarly
you --> me
search --> don't search
for --> never
any --> trip
I want a SINGLE Regular Expression with search and replaces and returns a SINGLE String after replacing all.
I don't like to iterate one by one and applying regex for each from and to value. Instead i want to iterate the array and form a SINGLE Regulare expression and use to replace the contents of the Entire String.
One Single regular expression which matches the pattern and solve the issue.
the output should be as:
If me wish to don't search never trip etc...,
Please help me to resolve this.
Thanks In Advance,
Kathir

Answer 1

As stated, no, it can't be done. But that doesn't mean you have to make a separate pass over the input for each word you want to replace. You can employ a regex that matches any word, then use the lower-level Matcher methods to replace the word or not depending on what was matched. Here's an example: import java.util.*;
import java.util.regex.*;
public class Test
  static final List<String> oldWords =
      Arrays.asList("you", "search", "for", "any");
  static final List<String> newWords =
      Arrays.asList("me", "dont search", "never", "trip");
  public static void main(String[] args) throws Exception
    String str = "If you wish to search for any of these characters, "
        + "they must be preceded by the character to be interpreted";
    System.out.println(doReplace(str));
  public static String doReplace(String str)
    Pattern p = Pattern.compile("\\b\\w+\\b");
    Matcher m = p.matcher(str);
    StringBuffer sb = new StringBuffer();
    while (m.find())
      int pos = oldWords.indexOf(m.group());
      if (pos > -1)
        m.appendReplacement(sb, "");
        sb.append(newWords.get(pos));
    m.appendTail(sb);
    return sb.toString();
} This is just a demonstration of the technique; a real-world solution would require a more complicated regex, and I would probably use a Map instead of the two Lists (or arrays).