How can I remove punctuation from input text in Java

Question

I am trying to get a sentence using input from the user in Java  and i need to make it lowercase and remove all punctuation  Here is my code       String   words   instring split    s         for  int i   0  i  lt  words length  i              words i    words i  toLowerCase              String   wordsout   new String 50       Arrays fill wordsout          int e   0      for  int i   0  i  lt  words length  i              if  words i                       wordsout e    words e               wordsout e    wordsout e  replaceAll                       e                        return wordsout    I cant seem to find any way to remove all non-letter characters  I have tried using regexes and iterators with no luck  Thanks for any help

User · Answer

If you don t want to use RegEx  which seems highly unnecessary given your problem   perhaps you should try something like this   public String modified final String input       final StringBuilder builder   new StringBuilder        for final char c   input toCharArray            if Character isLetterOrDigit c               builder append Character isLowerCase c    c   Character toLowerCase c        return builder toString        It loops through the underlying char   in the String and only appends the char if it is a letter or digit  filtering out all symbols  which I am assuming is what you are trying to accomplish  and then appends the lower case version of the char

User · Answer

You may try this -  Scanner scan   new Scanner System in   System out println  Type a sentence and press enter     String input   scan nextLine    String strippedInput   input replaceAll    W        System out println  Your string      strippedInput        w  matches a non-word character  so the above regular expression will match and remove all non-word characters

User · Answer

You can use following regular expression construct       Punctuation  One of       amp       -     lt                 inputString replaceAll    p Punct

User · Answer

This first removes all non-letter characters  folds to lowercase  then splits the input  doing all the work in a single line   String   words   instring replaceAll    a-zA-Z         toLowerCase   split    s       Spaces are initially left in the input so the split will still work   By removing the rubbish characters before splitting  you avoid having to loop through the elements

User · Answer

I don t like to use regex  so here is another simple solution   public String removePunctuations String s        String res           for  Character c   s toCharArray              if Character isLetterOrDigit c               res    c            return res      Note  This will include both Letters and Digits

[java] How can I remove punctuation from input text in Java?

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