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  1. #1
    iNko is offline Member
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    Default Can i use pregmatch in java code if statement?

    I remember i did some things with pregmatch in php, does it work the same way in java?

    If so, can someone help me get a correct 'pregmatch' for my textfields? In particular i need to check if:
    -only spaces entered in textfield
    -only numbers entered in textfield

    Also, can i insert this 'pregmatch' in a if statement, like this?
    Java Code:
    if(jTextField1.getText().equals(PREGMATCH) || jTextField1.getText().equals(PREGMATCH2) {
    }

  2. #2
    doWhile is offline Moderator
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    Default Re: Can i use pregmatch in java code if statement?

    Did you try it? What happened? Here's a good tutorial for how to use regular expressions in java:
    Lesson: Regular Expressions (The Java™ Tutorials > Essential Classes)
    There are methods in the String class (eg matches) that use regular expressions.

  3. #3
    iNko is offline Member
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    Default Re: Can i use pregmatch in java code if statement?

    Thanks ill look into regular expressions

  4. #4
    iNko is offline Member
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    Default Re: Can i use pregmatch in java code if statement?

    i found something like this:
    Java Code:
    String number = ...
    if (number.matches("^8\\d{9}$")) {
      // it's a number
    }
    would this work?:
    Java Code:
    if (jTextField1.matches("^8\\d{9}$")) {
    }
    also, how do i make it so it would be an opposite of 'matches'?

  5. #5
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Can i use pregmatch in java code if statement?

    Quote Originally Posted by iNko View Post
    i found something like this:
    Java Code:
    String number = ...
    if (number.matches("^8\\d{9}$")) {
      // it's a number
    }
    would this work?:
    Java Code:
    if (jTextField1.matches("^8\\d{9}$")) {
    }
    also, how do i make it so it would be an opposite of 'matches'?
    That's a very funny regular expression, i..e. it matches a number starting with an 8, followed by nine digits; is this what you had in mind? w.r.t. your last question: if 'x' is a boolean expression then !x is true whenever x is false and vice versa. Don't fall in the trap that you want to do everything with regular expressions ...

    kind regards,

    Jos
    The only person who got everything done by Friday was Robinson Crusoe.

  6. #6
    iNko is offline Member
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    Default Re: Can i use pregmatch in java code if statement?

    That expression is just a random expression that i found on google, i absolutely dont understand how they work (spent a couple of hours reading a 'simple' tutorial, and still couldnt understand anything..).
    Right now im just looking for an expression that would check if the textfield is a whole number, maximum 5 digits.

    Also for the 2nd part of my question, if i had this for example:
    Java Code:
    if (jTextField1.isEmpty(){
    }
    The opposite would be:
    Java Code:
    if (!jTextField1.isEmpty(){
    }
    Right? (dont know where to write '!').

  7. #7
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Can i use pregmatch in java code if statement?

    Quote Originally Posted by iNko View Post
    That expression is just a random expression that i found on google, i absolutely dont understand how they work (spent a couple of hours reading a 'simple' tutorial, and still couldnt understand anything..).
    Right now im just looking for an expression that would check if the textfield is a whole number, maximum 5 digits.

    Also for the 2nd part of my question, if i had this for example:
    Java Code:
    if (jTextField1.isEmpty(){
    }
    The opposite would be:
    Java Code:
    if (!jTextField1.isEmpty(){
    }
    Right? (dont know where to write '!').
    That would be right if jTextField1 would be a String; the name suggests otherwise so I guess it should be jTextField1.getText().isEmpty() or (to check if the String is not empty): !jTextField1.getText().isEmpty(). A String that contains at most five digits only, matches the regular expression "\\d{,5}"

    kind regards,

    Jos
    The only person who got everything done by Friday was Robinson Crusoe.

  8. #8
    DarrylBurke's Avatar
    DarrylBurke is offline Forum Police
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    Default Re: Can i use pregmatch in java code if statement?

    Quote Originally Posted by iNko View Post
    Also for the 2nd part of my question, if i had this for example:
    Java Code:
    if (jTextField1.isEmpty(){
    }
    The opposite would be:
    Java Code:
    if (!jTextField1.isEmpty(){
    }
    Right? (dont know where to write '!').
    What happened when you tried it?

    db
    If you're forever cleaning cobwebs, it's time to get rid of the spiders.

  9. #9
    iNko is offline Member
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    Default Re: Can i use pregmatch in java code if statement?

    Quote Originally Posted by JosAH View Post
    That would be right if jTextField1 would be a String; the name suggests otherwise so I guess it should be jTextField1.getText().isEmpty() or (to check if the String is not empty): !jTextField1.getText().isEmpty(). A String that contains at most five digits only, matches the regular expression "\\d{,5}"

    kind regards,

    Jos
    Thank you, this worked for me:
    Java Code:
    if ( !jTextField.getText().matches("^\\d{1,5}$") ){
    }

  10. #10
    JosAH's Avatar
    JosAH is offline Moderator
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    Default Re: Can i use pregmatch in java code if statement?

    Quote Originally Posted by iNko View Post
    Thank you, this worked for me:
    Java Code:
    if ( !jTextField.getText().matches("^\\d{1,5}$") ){
    }
    Note that you don't need the ^...$ because the matches( ... ) method tries to match the entire String, i.e. "\\d{1,5}" is enough.

    kind regards,

    Jos
    The only person who got everything done by Friday was Robinson Crusoe.

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