NSString find the symbol got crashed - objective-c

Question

Everytime I will get a string from my server as:
"&abc;123:342:431:234& &xyz;232:2344:433:434& &pqr;234:453:534:3445&"
but sometimes I'll get
"&pqr;234:453:534:3445& &abc;123:342:431 &xyz;232:2344:433:434&"
I want to discard those messages (without ends with "&") ex:&abc;123:342:431. I tried but I don't know where I am making mistakes.
Here is my code:
- (BOOL)ashCheckandsemiclonCheck:(NSString *)string {
if([string rangeOfString:#"&abc"].location != NSNotFound) {
NSLog(#"is here");
NSString *pattern = #"&abc[^&]+&";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern
options:0 error:NULL];
[regex enumerateMatchesInString:string options:0 range:NSMakeRange(0, [string length])
usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
NSRange range = [result range];
matched = [string substringWithRange:range];
NSLog(#"%#", matched);
}];
NSLog(#"filtered Message :%#", matched);
int times = [[matched componentsSeparatedByString:#"&"] count] - 1;
NSLog(#"counted times :%i", times);
if (times == 2) {
return TRUE;
} else {
return FALSE;
}
} else {
return FALSE;
}
}
I want to call this argument if I have two & but in my code I get error NSLog(#"is here");. As I said sometimes I'll get half message. Can anyone tell me where I am going wrong?

Answer 1

If I'm reading your question correctly, it seems you just need to test whether a message string is valid by checking it begins and ends with '&'. The way I'd do that is to write something like this:
NSString* testMessage = #"&bfjhfbgfjhb&";
NSString* firstCharacter = [testMessage substringToIndex:1];
NSString* lastCharacter = [testMessage substringFromIndex:testMessage.length - 1];
if (([firstCharacter isEqualToString:#"&"]) &&
[lastCharacter isEqualToString:#"&"]){
//This is a valid message. Proceed.
}else{
//This is not a valid message. Discard.
}
Update
Okay, based on your question edit/update, I edited your code -- and in particular your regex pattern string -- to do what I think you want, which is to check that the '&abc...' subsection of your message begins and ends with the '&' character:
-(BOOL) ashCheckandsemiclonCheck :(NSString *)string;
{
if([string rangeOfString:#"&abc"].location !=NSNotFound)
{
NSLog(#"is here");
NSString *pattern = #"&abc[^&\\s]+[^\\s]";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern
options:0 error:NULL];
NSString* __block matched;
[regex enumerateMatchesInString:string options:0 range:NSMakeRange(0, [string length])
usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
NSRange range = [result range];
matched = [string substringWithRange:range];
NSLog(#"Matched: %#", matched);
}];
NSLog(#"filtered Message :%#", matched);
int times =[[matched componentsSeparatedByString:#"&"]count]-1;
NSLog(#"counted times :%i",times);
if(times ==2){
return YES;
}else
{
return NO;
}
}
else
{
return NO;
}
}
Also changed your BOOL returns to Objective-C standard YES and NO rather than TRUE and FALSE.
Hope that does what you need.