isEqualToString:没有正确比较字符串

Question

我有两个完全相同的字符串,但它们没有被比较为相等.一个字符串是一个可变字符串,另一个是普通字符串,我有一个if语句来检查两个字符串是否相等.两个字符串的输出是这样的:

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

顶部是可变字符串,底部是普通字符串.我已经尝试将可变字符串转换为普通字符串,但我遇到了同样的问题.我从NSXMLParser子类中的xml文档获取可变字符串,另一个从单例中的可变数组中获取.以下是NSXMLParser类的代码:

- (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");
        }
    }
}

所以我正在比较这两个地址,并设置一个属性,如果地址是相同的,我已经确定将永远是真的.有人看到有什么不对吗？我真的不知道为什么会这样.

Answer 1

尝试在比较它们之前修剪字符串中的空格字符.您可以使用以下内容

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