Comparing NSString

ossama · January 2011

Hi

i have tried all my best but just cant get to a solution

I would like to compare incoming socket against i.e @"ack"

here is the code

the incoming string:

NSString *str = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

compare to:

NSString *str1 = @"ack";

comparison code:

if ([str isEqualToString:str1]) {
label.text = str;
}

when I nslog(str,nil) it shows that it equals ack

but when i compare it to ack it doesn't matchhhh :(

any ideas please

baja_yu · January 2011

There's no need to post the same question multiple times.

Are they exact in regards to case?

baja_yu · January 2011

Just ran this and it worked ok:


	NSString *str1 = @\"ack\";
	NSData *data = [str1 dataUsingEncoding:NSASCIIStringEncoding];
	NSString *str2 = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
	if ([str2 isEqualToString:@\"ack\"]) {
		NSLog(@\"It's equal\");
	}
	[str2 release];

ossama · January 2011

Thanks mate, but i tried it already and not working

the strange thing is that if i convert str to integer it works as highlighted below

here is all the code


- (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {
    
    switch(eventCode) {
        case NSStreamEventHasBytesAvailable:
        {
            if (data == nil) {
                data = [[NSMutableData alloc] init];
            }
            uint8_t buf[1024];
            unsigned int len = 0;
            len = [(NSInputStream *)stream read:buf maxLength:1024];
            if(len) {    
                [data appendBytes:(const void *)buf length:len];
                int bytesRead;
                bytesRead += len;
            } else {
                NSLog(@\"No data.\");
            }
           
            NSString *str = [[NSString alloc] initWithData:data 
												  encoding:NSASCIIStringEncoding];
			NSLog(str,nil);
						
			if ([str isEqualToString:@\"ack\"]) {
				NSLog(@\"It's equal\");
			label.text = str;
			}
			
			else {
				label.text = @\"\";
				txtMessage.backgroundColor = [UIColor clearColor];
				txtMessage.text = str; 
			}
				
[COLOR=\"Red\"][B]This below works by the way[/B][/COLOR]
				int x = [str intValue];
				[COLOR=\"Blue\"]if (x > 30)
				{
					//txtMessage.text = @\"High\";  
					label.text = @\"High temperature\";
					txtMessage.backgroundColor = [UIColor redColor];
					txtMessage.text = str; 
					
				}[/COLOR]
			           
			[str release];
            [data release];        
            data = nil;
			 
        } break;
    }
}

bluemonkey · January 2011

What's the output of NSString *str = [[NSString alloc] initWithData:data

If you do NSLog(@"output = %@", str);

ossama · January 2011

2011-01-13 21:42:17.765 Socket[57886:207] output = ack

dany_dev · January 2011

strange, isEqualToString should solve problems about encoding, are you sure that there isn't strange characters? maybe a space, or something other in str, maybe terminator character \0?

RLScott · January 2011

Like Dany88 said, check for non-visible characters. What is the output of

NSLog(@\"output = %@ and length = %d\", str, str.length);

We know the length of @"ack" should be 3.

ossama · January 2011

It is possible that the server is sending ack with the /n
Not too sure
If it is, what should I try
@"ack/n" ??

ossama · January 2011

2011-01-13 23:05:46.633 Socket[58689:207] output = ack
and length = 4

Thanks for your help

does it mean there is a terminating character \0
any ideas how to compare against that.

:)

RLScott · January 2011

ossama;286901 said:
2011-01-13 23:05:46.633 Socket[58689:207] output = ack
and length = 4

Thanks for your help

does it mean there is a terminating character \0
any ideas how to compare against that.

:)

Did you post "and length = 4" on a separate line deliberately, or did the newline just appear? It looks like there is a newline character in your data. That makes sense if it came from a text file.

dany_dev · January 2011

str = [str stringByReplacingOccurancesOfString:@"\n" withString:@""];

ossama · January 2011

no, the new line just appeared. not deliberate which means there is a carriage return

I tried

str = [str stringByReplacingOccurancesOfString:@\"\n\" withString:@\"\"];

but i get an error and the app quits after trying to connect to server

warning: 'NSString' may not respond to '-stringByReplacingOccurancesOfString:withString:'

ossama · January 2011

this seems to have fixed the problem I believe, I will test this later, getting very late now

if ([str isEqualToString:@\"ack\n\"])

ossama · January 2011

Thanks for your time and help.
if you ever need help, yell at me :)

Howdy, Stranger!

Forums

Comparing NSString

Replies