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

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

[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

Pretty simple, easy to understand version avoiding NSRange stuff:

NSArray * words = [string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]; NSMutableArray * mutableWords = [NSMutableArray new];for (NSString * word in words){    if ([word length] > 1 && [word characterAtIndex:0] == '#'){        NSString * editedWord = [word substringFromIndex:1];        [mutableWords addObject:editedWord];    }}