Question

我有这样一份定购单:

aaa
bbb
ccc
ddd
eee

我想核实档案中是否存在“dd”扼杀。

Here my func:

- (BOOL) asd:(NSString*)sting 
{
NSArray *LinesCount = 
  [[NSString stringWithContentsOfFile:@"longfile.txt"  
   encoding:NSStringEncodingConversionAllowLossy error:nil]   
    componentsSeparatedByString:@"
"];

unsigned index = (unsigned)CFArrayBSearchValues(
                 (CFArrayRef)LinesCount, 
                 CFRangeMake(0, CFArrayGetCount((CFArrayRef)LinesCount)),
                 (CFStringRef)string, 
                 (CFComparatorFunction)CFStringCompare, 
                 NULL);
if (index < [LinesCount count]) return YES;
return NO;
}

为什么它总是以任何扼杀方式返回?

Answer 1

The problem is in the way you read in the array. If you replace the code that assigns LineCount with

NSArray * LinesCount = [NSArray arrayWithObjects:@"aaa", @"bbb", @"ccc", @"ddd", @"eee", nil];

you will see the binary search performs fine.

贵国法典中有两个问题:

Line separator is probably just " " if the file has been created on Mac OS X
Your array will contain a left over "" as it s last element hence the requirement for ordering as required by CFArrayBSearchValues is no longer satisfied.

例如:

 NSLog(@"%@", [@"one
two
" componentsSeparatedByString:@"
"]);

产量(指最后一个空数):

 2011-09-29 16:52:33.024 a.out[4019:707] (
     one,
     two,
     ""
 )

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