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Thread: need help with regex

  1. #1
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    Default need help with regex

    my program has to output and evaluate a string,

    heres 3 examples of how it is supposed to run,

    eg.1 (no string entered)
    java Word
    Usage: java Word <string>


    eg.2(string containing punctuation and numbers gives the output "The string must consist of letters!")
    java Word AAABB@I5P
    The string must consist of letters!


    eg.3(continous character gives the output)
    java Word AAAAAAAwwwwwwwwwwwTTT
    7A11w3T


    and heres the code i got so far

    [COLOR="Blue"]import java.util.Scanner;
    import java.io.PrintStream;
     
    public class Word
    {
    public static void main(String[] args)
    {
    Scanner input = new Scanner(System.in);
    PrintStream output = System.out;
     
    output.print("java Word ");
    String s = input.nextLine();
    if (s.equals(""))
    {
    output.print("Usage: java Word <string>");
    }
    if (s.matches("[^0-9]*[0-9]+[^0-9]*"))
    {
    output.print("The string must consist of letters!");
    }
    if (s.matches("[\\p]")) [COLOR="SeaGreen"]//is this the correct code for all punctuations??[/COLOR]
    {
    output.print("The string must consist of letters!");
    }
     
    }
    }[/COLOR]


    when i enter a number i get the correct output, however I am not sure on how to exclude punctuations from the string and i get a weird error when typing in [\\p],
    Last edited by o2a1; February 12th, 2011 at 08:49 AM.


  2. #2
    Administrator copeg's Avatar
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    Default Re: need help with regex

    All you want is letters right? The simple letter matcher should suffice [a-zA-Z]. See Regular Expressions for more info and possible combinations

    Edit: crossposted at need help with regex. Please read The problems with crossposting
    Last edited by copeg; February 12th, 2011 at 10:52 AM.

  3. #3
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    Default Re: need help with regex

    my bad for crossposting,, but i didnt think i would get a reply, wont happen again,
    ok so i put

    if (s.matches("[a-zA-Z]"))
    {
    output.print("The string must consist of letters!");
    }

    but if i add a number or punctuation the output "The string must consist of letters!" does not show,
    if i use a negation like (!s.matches("[a-zA-Z]") then if i input letters and number or punctuations, the output "The string must consist of letters!" always show,,
    however if i use (s.matches("[^a-zA-Z]") then if i input numbers and punctuations then i get the correct output but say if i type in "aa2" as an input then the output "The string must consist of letters!" does not show,,
    i want to exclude numbers and punctuation completely from the string but dont know how :S
    u said "The simple letter matcher should suffice [a-zA-Z]",, can u clarify this for me? this whole regex thing is confusing for me :S
    Last edited by o2a1; February 12th, 2011 at 07:23 PM.

  4. #4
    Administrator copeg's Avatar
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    Default Re: need help with regex

    my bad for crossposting
    We just ask you be forthright and understand the problems.

    Add a quantifier to the regex, [a-zA-Z]+ will match a word of all letters (lower and uppercase) of length 1 or greater.

  5. The Following User Says Thank You to copeg For This Useful Post:

    o2a1 (February 13th, 2011)

  6. #5
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    Default Re: need help with regex

    ahh thank you,, got it,,
    (!s.matches("[a-zA-Z]+") did the trick,,

    hope i can get the next part done

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