finding decimals in string
finding decimals in string
- Subject: finding decimals in string
- From: Daniel Child <email@hidden>
- Date: Fri, 24 Aug 2007 16:04:26 -0400
Hi All,
I have been looking at the NSScanner and NSCharacterSet classes for a
way to find
out whether a string contains digits. I thought something along these
lines might work:
/********************************************************* FUNCTIONAL
METHODS **
* evaluateText
*
* Evaluates whether the textInput field contains numbers and stores
that result
* in the hasNumbers instance variable.
************************************************************************
*******/
- (void) evaluateText
{
NSCharacterSet *numberChars;
NSScanner *scanner;
NSMutableString *numbersFound;
numberChars = [NSCharacterSet decimalDigitCharacterSet];
scanner = [NSScanner scannerWithString: [self textInput]];
numbersFound = [NSMutableString string];
[scanner scanCharactersFromSet: numberChars intoString: &numbersFound];
NSLog(@"The character set is %@\n", numberChars);
if ([numbersFound length] == 0) {
NSLog(@"No numbers were found.\n");
[self setHasNumbers: NO];
}
else {
NSLog(@"The numbers found were %@\n", numbersFound);
[self setHasNumbers: YES];
}
}
When I run the debugger, numbersFound gets assigned its memory space,
but no numbers get scanned in. The value of the instance variable
textInput was "one1two2three3", so it should have scanned in some
numbers. My output from the logs is:
2007-08-24 16:02:24.017 CheckForNumbers[1012] Init method went well.
2007-08-24 16:02:24.019 CheckForNumbers[1012] The character set is
<NSBuiltinCharacterSet: 0x306c10>
2007-08-24 16:02:24.019 CheckForNumbers[1012] No numbers were found.
I must be missing something obvious about the way this scanner
function works. I am also wondering if this is the normal approach to
find out whether a string contains certain characters of interest. Or
is there a class I don't know about?
Much thanks.
Daniel
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