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Some Integer check method

Posted on 2006-07-21
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Last Modified: 2010-03-31
Hey experts,

 Is there any java built-in method similar to VB's IsNumeric method; I need a methd that checks if a string variable is an integer or no. I know I can do it by trying to instantiate a new object of class Integer, and an exception would occur if it's not an integer, but I am trying to see if there is a better way.....any help??
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Question by:mte01
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9 Comments
 
LVL 86

Expert Comment

by:CEHJ
ID: 17155581
Long.parseLong(x)

will throw an Exception if not a number
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LVL 3

Author Comment

by:mte01
ID: 17155628
>>CEHJ

I am trying to see something better than having to check for an exception....the Integer.getInteger method seems good enough....
0
 
LVL 2

Assisted Solution

by:RoyalNepal
RoyalNepal earned 50 total points
ID: 17155812
No...there is no such built in function in java...

Two ways:

1)Throws an exception if its not a number..
2) write a function...

//Here is the code for that.....

private static final boolean isNumeric(final String s) {
  final char[] numbers = s.toCharArray();
  for (int x = 0; x < numbers.length; x++) {      
    final char c = numbers[x];
    if ((c >= '0') && (c <= '9')) continue;
    return false; // invalid
  }
  return true; // valid
}

Cheers.

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LVL 86

Accepted Solution

by:
CEHJ earned 300 total points
ID: 17156159
An exception-free method would be

if (s.matches("\\d+"))
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LVL 3

Author Comment

by:mte01
ID: 17156609
>>CEHJ

Great..that'll do the trick...thanks for your help!
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LVL 86

Expert Comment

by:CEHJ
ID: 17156728
:-)
0
 
LVL 26

Expert Comment

by:ksivananth
ID: 17156930
i think it should be ^\\d+, simply \\d going to return true if there is a number
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LVL 86

Expert Comment

by:CEHJ
ID: 17157056
>>simply \\d going to return true if there is a number

No. Returns true if *only* a number
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LVL 26

Expert Comment

by:ksivananth
ID: 17157084
agree

confused with find method
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