isEqualToString: not comparing strings correctly

Question

I have two strings that are exactly the same, but they are not being compared as equal. One string is a mutable string, and the other is a normal string, and I have a if statement that checks if the two strings are equal. The output for the two strings is this:

2013-04-08 09:09:31.555 Pin2Own[650:1303] 6447 E Crocus Dr
2013-04-08 09:09:31.555 Pin2Own[650:1303] 6447 E Crocus Dr

The top is a mutable string, and the bottom is the normal string. I have tried converting the mutable string to a normal string, but I am having the same problem. I am getting the mutable string from a xml document in a NSXMLParser subclass, and the other from a mutable array in a singleton. Here is the code for the NSXMLParser class:

- (void)parserDidStartDocument:(NSXMLParser *)parser
{
    address = nil;
    zpid = nil;
}

- (void)parser:(NSXMLParser *)parser
didStartElement:(NSString *)elementName
  namespaceURI:(NSString *)namespaceURI
 qualifiedName:(NSString *)qualifiedName
    attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"street"])
    address = [[NSMutableString alloc] init];

    if ([elementName isEqualToString:@"zpid"])
    zpid = [[NSMutableString alloc] init];
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    if(address)
    [address setString:string];

    else if(zpid)
    [zpid setString:string];
}

- (void)parser:(NSXMLParser *)parser
 didEndElement:(NSString *)elementName
  namespaceURI:(NSString *)namespaceURI
 qualifiedName:(NSString *)qName
{
    if ([elementName isEqualToString:@"street"])
    NSLog(@"%@", address);

    if ([elementName isEqualToString:@"zpid"])
    NSLog(@"zip id is: %@", zpid);
}

- (void)parserDidEndDocument:(NSXMLParser *)parser
{    
    NSMutableArray *annotations = [[Data singleton] annotations];

    for (MapPoint *mp in annotations)
    {
        NSLog(@"%@", mp.fullAddress);
        if ([mp.fullAddress isEqualToString:address])
        {
            mp.zpid = zpid;
        }
        else
        {
            NSLog(@"Did not match address");
        }
    }
}

SO I am comparing the two addresses, and setting a property if the addresses are the same, which I have made sure will always be true. Does anyone see if there is something wrong? I really have no idea why this is happening.

Answer 1

try trimming the whitespace characters from your strings before comparing them. You can use the following

firstString = [firstString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
secondString = [secondString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
BOOL stringsAreEqual = [firstString isEqualToString:secondString];