Question

I’m using this method to find the first <> couple into a string (XML content) :

NSScanner* scanner = [NSScanner scannerWithString:contentToParse];
int startPos = 0;
int endPos = 0;

// Open search
if ([scanner scanString:@"<" intoString:nil]) {
    startPos = [scanner scanLocation]-1;
    NSLog(@"found '<' at pos %i", startPos);

    // close search
    if ([scanner scanString:@">" intoString:nil]) {
        endPos = [scanner scanLocation]-1;
        NSLog(@"found '>' at pos %i", endPos);

        NSString* tag = [contentToParse substringWithRange:NSMakeRange(startPos, endPos-startPos)];
        NSLog(@"Tag found : %@", tag);
    }
}

but only “found ‘<‘ at pos 0” is logged.
My XML content contains many many <> items…

Why is that method not working ?

Answer 1

scanString:intoString: tries to scan the string parameter at the current location. If such string is not present at the current location, it simply returns NO.

You may want use scanUpToString:intoString: (reference) instead, which scans advancing the scan location until the given string is encountered.

NSScanner *scanner = [NSScanner scannerWithString:contentToParse];
// open search
[scanner scanUpToString:@"<" intoString:nil];
if (![scanner isAtEnd]) {
    [scanner scanString:@"<" intoString:nil];
    // close search
    NSString *tag = nil;
    [scanner scanUpToString:@">" intoString:&tag];
    if (![scanner isAtEnd]) {
        NSLog(@"Tag found : %@", tag);
    }
}