Finding first letter in NSString and counting backwards - ios

Question

I'm new to IOS, and was looking for some guidance.
I have a long NSString that I'm parsing out. The beginning may have a few characters of garbage (can be any non-letter character) then 11 digits or spaces, then a single letter (A-Z). I need to get the location of the letter, and get the substring that is 11 characters behind the letter to 1 character behind the letter.
Can anyone give me some guidance on how to do that?
Example: '!!2553072 C'
and I want : '53072 '

Answer 1

You can accomplish this with the regex pattern: (.{11})\b[A-Z]\b
The (.{11}) will grab any 11 characters and the \b[A-Z]\b will look for a single character on a word boundary, meaning it will be surrounded by spaces or at the end of the string. If characters can follow the C in your example then remove the last \b. This can be accomplished in Objective-C like so:
NSError *error;
NSString *example = #"!!2553072 C";
NSRegularExpression *regex = [NSRegularExpression
regularExpressionWithPattern:#"(.{11})\\b[A-Z]\\b"
options:NSRegularExpressionCaseInsensitive
error:&error];
if(!regex)
{
//handle error
}
NSTextCheckingResult *match = [regex firstMatchInString:example
options:0
range:NSMakeRange(0, [example length])];
if(match)
{
NSLog(#"match: %#", [example substringWithRange:[match rangeAtIndex:1]]);
}

Answer 2

There may be a more elegant way to do this involving regular expressions or some Objective-C wizardry, but here's a straightforward solution (personally tested).
-(NSString *)getStringContent:(NSString *)input
{
NSString *substr = nil;
NSRange singleLetter = [input rangeOfCharacterFromSet:[NSCharacterSet letterCharacterSet]];
if(singleLetter.location != NSNotFound)
{
NSInteger startIndex = singleLetter.location - 11;
NSRange substringRange = NSMakeRange(start, 11);
substr = [tester substringWithRange:substringRange];
}
return substr;
}

Answer 3

You can use NSCharacterSets to split up the string, then take the first remaining component (consisting of your garbage and digits) and get a substring of that. For example (not compiled, not tested):
- (NSString *)parseString:(NSString *)myString {
NSCharacterSet *letters = [NSCharacterSet letterCharacterSet];
NSArray *components = [myString componentsSeparatedByCharactersInSet:letters];
assert(components.count > 0);
NSString *prefix = components[0]; // assuming relatively new Xcode
return [prefix substringFromIndex:(prefix.length - 11)];
}

Answer 4

//to get rid of all non-Digits in a NSString
NSString *customerphone = CustomerPhone.text;
int phonelength = [customerphone length];
NSRange customersearchRange = NSMakeRange(0, phonelength);
for (int i =0; i < phonelength;i++)
{
const unichar c = [customerphone characterAtIndex:i];
NSString* onechar = [NSString stringWithCharacters:&c length:1];
if(!isdigit(c))
{
customerphone = [customerphone stringByReplacingOccurrencesOfString:onechar withString:#"*" options:0 range:customersearchRange];
}
}
NSString *PhoneAllNumbers = [customerphone stringByReplacingOccurrencesOfString:#"*" withString:#"" options:0 range:customersearchRange];