Problem with NSRange in Objective-C?

Question

I have a little problem with NSRange, or maybe its just the wrong comman I use.

Here is what I want to do. I have a string like this :

NSString *mystring = @"/c1blue/c2green/c3yellow/"

As you can see there is always a command with a value and that seperated by "/". Now I want to write a mthod that gives me a specific value for a command, e.g. c2 which would be green.

First I would get the position of c2 :

int beginIndex = [mystring rangeOfString:@"c2"].location;

Now I need to find the position of the "/" with the offset of 'beginIndex'.

And thats where I do not know how.

Help is hihly appreciated. Thanks

Answer 1

Another approach:

NSString *getCommand(NSString *string, NSString *identifier)
{
    for (NSString *component in [string componentsSeparatedByString:@"/"])
    {
        NSRange range=[component rangeOfString:identifier];
        if (range.location==0) {
            return [component substringFromIndex:range.length];
        }
    }
    return nil;
}

Test code:

NSString *mystring = @"/c1blue/c2green/c3yellow/";
NSLog(@"%@", getCommand(mystring, @"c2"));
NSLog(@"%@", getCommand(mystring, @"c3"));
NSLog(@"%@", getCommand(mystring, @"c4"));  

Result:

2011-01-06 15:31:13.706 so[3949:a0f] green
2011-01-06 15:31:13.711 so[3949:a0f] yellow
2011-01-06 15:31:13.712 so[3949:a0f] (null)

Answer 2

How about splitting the string into array first, using the componentsSeparatedByString: method of NSString?

Answer 3

How about this:

NSString *mystring = @"/c1blue/c2green/c3yellow/";
NSMutableDictionary *commands=[NSMutableDictionary dictionary];
for (NSString *component in [mystring componentsSeparatedByString:@"/"])
{
    // assuming your identifier is always 2 characters...
    if ([component length]>2) {
        [commands setObject:[component substringFromIndex:2] forKey:[component substringToIndex:2]];
    }
}
NSLog(@"commands %@", commands);
NSLog(@"command c2: %@", [commands objectForKey:@"c2"]);

Result:

2011-01-06 15:21:27.117 so[3741:a0f] commands {
    c1 = blue;
    c2 = green;
    c3 = yellow;
}
2011-01-06 15:25:26.488 so[3801:a0f] command c2: green

Answer 4

Look at NSString reference and i think what you need is:

- (NSArray *)componentsSeparatedByString:(NSString *)separator

Answer 5

Thanks,

I actually came up with this one, but it looks more complicated than the suggested ones :

- (NSString *) CommSubStr:(NSString *) commandString withPattern:(NSString *) command
{
    int beginIndex = [commandString rangeOfString:command].location;
    if (beginIndex == -1)
    {
       return @"";
    } else
    {
        NSRange subStringRange = NSMakeRange(beginIndex + [command length], [commandString length]-(beginIndex+[command length]));
        NSString *newString = [commandString substringWithRange:subStringRange];

        int endIndex = [newString rangeOfString:@"/"].location;
        NSRange finalSubStringRange = NSMakeRange(0, endIndex);

        return [newString substringWithRange:finalSubStringRange];
    }
}