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Thread: Little easy to fix problem

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    Default Little easy to fix problem

    Hi guys (Using java ME but syntax is the same)

    I am new to java and also new to the forums

    I have a quick question that im sure you guys can help me with..

    How in java to you make sure that a username (textbox) has a number in it... for example jon will show an error messege but jon43 wont....

    here is my current code. I know this code works but I would like to know how do do it.... thanks

    if (ID.equals(""))
    {
    String Invalid = " UserID invalid ";
    mAlertInvalidUser.setString(StrmAlertInvalid);
    mDisplay.setCurrent(mAlertInvalid);


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    Default Re: Little easy to fix problem

    Recommended reading: Pattern (Java Platform SE 6)
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    Default Re: Little easy to fix problem

    Sorry I am very new and i dont understand most of what I just read... could you give some more assistance to my problem

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    Default Re: Little easy to fix problem

    That link talks about regular expressions. Basically, regular expressions tell you whether a particular pattern (like a number) can be found inside another String.

    Hint- The pattern you're looking for is any number of any kind of character, then a number, then any number of any kind of character, right?
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    Default Re: Little easy to fix problem

    yes indeed. so if its jon it kicks up an error but if its jon23 it does not

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    Default Re: Little easy to fix problem

    Quote Originally Posted by adammint7 View Post
    yes indeed. so if its jon it kicks up an error but if its jon23 it does not
    Yep. So your next step is to throw together a regular expression that matches that pattern.
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    Default Re: Little easy to fix problem

    This is the thing.. I am not sure how. could you give me an example??

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    Default Re: Little easy to fix problem

    Quote Originally Posted by adammint7 View Post
    This is the thing.. I am not sure how. could you give me an example??
    Google is your friend for example regular expressions. But here's one that tests whether the String "cat" can be found in another String:
    Pattern p = Pattern.compile(".*cat.*");
    		 Matcher m = p.matcher("test cat test");
    		 boolean b = m.matches();
     
    		 System.out.println(b);
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    Default Re: Little easy to fix problem

    how would I put that into an if statement for names, I have not used that methodology before

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    Default Re: Little easy to fix problem

    Quote Originally Posted by adammint7 View Post
    how would I put that into an if statement for names, I have not used that methodology before
    What have you tried? Which part of that are you stuck on? Iterating over names? Using an if statement? Something else? You can't just keep asking general questions, as they're actually much harder to answer than specific questions about code.

    Post an SSCCE (not your entire program) that demonstrates what you've tried and where you're stuck and ask a specific question, and we'll go from there.
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