Remove certain characters from string

Question

I want to create a program that gives the number of characters, words, etc... in a user-inputted string. To get the word count I need to remove all the periods and commas form a string. So far I have this:

import javax.swing.JOptionPane;
public class WordUtilities
{
   public static void main(String args[])
   {
      {
      String s = JOptionPane.showInputDialog("Enter in any text.");

      int a = s.length();
      String str = s.replaceAll(",", "");
      String str1 = str.replaceAll(".", "");
      System.out.println("Number of characters: " + a);
      System.out.println(str1);
      }
   }
}

But in the end I get only this:

Number of characters: (...)

Why is it not giving me the string without the commas and periods? What do I need to fix?

cause replaceAll exepcts a regex.. and `.` is a special symbol — nachokk, Dec 31 '13 at 18:52
@nachokk So what syntax do I have to use to remove the special symbols (. and ,)? — f3d0r, Dec 31 '13 at 18:53
You'll need to remove more than just a period and a comma: colons, semicolons, dashes (as opposed to hyphens), apostrophes, double quotes... it's better to remove everything except what you want to count as a character. — , Dec 31 '13 at 19:00
@dasblinkenlight s = str.replaceAll("[.]","") from the other question fixed it. Thanks — f3d0r, Dec 31 '13 at 19:02

score 11 · Accepted Answer · answered Dec 31 '13 at 18:58

11

You can use:

String str1 = str.replaceAll("[.]", "");

instead of:

String str1 = str.replaceAll(".", "");

As @nachokk said, you may want to read something about regex, since replaceAll first parameter expects for a regex expression.

Edit:

Or just this:

String str1 = s.replaceAll("[,.]", "");

to make it all in one sentence.

answered Dec 31 '13 at 18:58

Christian Tapia

33,620
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1

The `.` still needs to be escaped to `"[\.]"` – Dec 31 '13 at 18:59
3

@JeremyMiller, not in a character class – Paul Samsotha Dec 31 '13 at 18:59
@peeskillet - I stand corrected. Thanks! – Dec 31 '13 at 19:05

nachokk · Answer 2 · 2013-12-31T19:05:34.540

4

You can just use String#replace() instead of replaceAll cause String#replaceAll

Replaces each substring of this string that matches the given regular expression with the given replacement.

So in code with replace is

 str = str.replace(",","");
 str = str.replace(".","");

Or you could use a proper regular expression all in one:

str = str.replaceAll("[.,]", "");

edited Dec 31 '13 at 19:05

answered Dec 31 '13 at 18:53

nachokk

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+1 for difference clarification – Paul Samsotha Dec 31 '13 at 19:00
You should reverse your code because the explanation is for the latter case – Paul Samsotha Dec 31 '13 at 19:03
@peeskillet i don't understand what you mean – nachokk Dec 31 '13 at 19:06
The code at the bottom matches your answer description. So put that code first. Then you can use the OR for the relaceAll case. Make more logically sense and will make your answer flow more smoothly – Paul Samsotha Dec 31 '13 at 19:07
1

I like your answer the best. People are so used to creating new strings, they forget you can just make the old string equal the modified string, but in which case, you should've used `s` instead of `str` – Paul Samsotha Dec 31 '13 at 19:13

Remove certain characters from string

2 Answers2