iOS 字符串的操作，去掉某一个字符或者替换成其他字符

NSString *strUrl = [urlString stringByReplacingOccurrencesOfString:@" " withString:@""];  去掉空格

NSString *strUrl = [urlString stringByReplacingOccurrencesOfString:@" " withString:@"/"];替换字符