find numbers in text file objective-c [duplicate] - objective-c

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Closed 10 years ago.
Possible Duplicate:
How to generate all of the numbers of pi in Objective-C
I want to implement "am i in pi" for searching birth date in pi numbers,
I have 1 million series of pi Numbers in .txt file, would you please give me some hints for implement this game?
what is the best way? how can I found my birth date in text file?
Thanks in advance

Answer 1

NSString* str = [NSString stringWithContentsOfFile: #"path to your file" encoding: NSASCIIStringEncoding error: nil];
NSRange rng = [str rangeOfString: #"1989"]; //here is the range of the birth year 1989

Answer 2

1 megabyte is sufficiently small that loading and then scanning it is reasonably straightforward. If you wanted to be a little clever, you could map the file into memory and then scan it through the map (avoiding the need to load the entire file into memory, which becomes more important for multi-hundred-MB files).
NSDataReadingOptions options = NSDataReadingMappedIfSafe | NSDataReadingUncached;
NSData *data = [NSData dataWithContentsOfFile:filename
options:options
error:nil];
NSString *string = [[NSString alloc] initWithData:data
encoding:NSASCIIStringEncoding];
NSRange range = [string rangeOfString:year];
[string release];
You could add appropriate error handling.

Answer 3

Once I wrote a category of NSString, which has method:
- (NSArray *)occurrencesOfSubstring:(NSString *)string
{
NSMutableArray *result = [NSMutableArray array];
NSRange range = NSMakeRange(0, self.length);
NSUInteger len = self.length;
while (range.location != NSNotFound) {
range = [self rangeOfString:string options:0 range:range];
if (range.location != NSNotFound) {
NSRange resRange = range;
[result addObject:[NSValue valueWithRange:resRange]];
range = NSMakeRange(NSMaxRange(resRange), len - NSMaxRange(resRange));
}
}
return result;
}
It returns array of ranges of searched substring. Hope it helps.