Objective-C: How to extract part of a String (e.g. start with '#')

Question

I have a string as shown below,

NSString * aString = @"This is the #substring1 and #subString2 I want"; 

How can I select only the text starting with '#' (and ends with a space), in this case 'subString1' and 'subString2'?

Note: Question was edited for clarity

Answer 1

[aString substringWithRange:NSMakeRange(13, 10)]  

would give you substring1

You can calculate the range using:

NSRange startRange = [aString rangeOfString:@"#"]; NSRange endRange = [original rangeOfString:@"1"];  NSRange searchRange = NSMakeRange(startRange.location , endRange.location); [aString substringWithRange:searchRange]  

would give you substring1

Read more: Position of a character in a NSString or NSMutableString

and

http://iosdevelopertips.com/cocoa/nsrange-and-nsstring-objects.html

Answer 2

You can do this using an NSScanner to split the string up. This code will loop through a string and fill an array with substrings.

NSString * aString = @"This is the #substring1 and #subString2 I want"; NSMutableArray *substrings = [NSMutableArray new]; NSScanner *scanner = [NSScanner scannerWithString:aString]; [scanner scanUpToString:@"#" intoString:nil]; // Scan all characters before # while(![scanner isAtEnd]) {     NSString *substring = nil;     [scanner scanString:@"#" intoString:nil]; // Scan the # character     if([scanner scanUpToString:@" " intoString:&substring]) {         // If the space immediately followed the #, this will be skipped         [substrings addObject:substring];     }     [scanner scanUpToString:@"#" intoString:nil]; // Scan all characters before next # } // do something with substrings [substrings release]; 

Here is how the code works:

1. Scan up to a #. If it isn't found, the scanner will be at the end of the string.
2. If the scanner is at the end of the string, we are done.
3. Scan the # character so that it isn't in the output.
4. Scan up to a space, with the characters that are scanned stored in substring. If either the # was the last character, or was immediately followed by a space, the method will return NO. Otherwise it will return YES.
5. If characters were scanned (the method returned YES), add substring to the substrings array.
6. GOTO 1