iOS开发之NSArray的过滤

//找出一个数组   
   NSFileManager *fileManager = [NSFileManager defaultManager];  
    NSString *defaultPath = [[NSBundle mainBundle] resourcePath];  
    NSError *error;  
      
    NSArray *directoryContents = [fileManager contentsOfDirectoryAtPath:defaultPath error:&error]  
//匹配字符串，反回结果， SELF＝＝表示数组中每一个元素  
NSString *match = @"imagexyz-999.png";  
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF == %@", match];  
    NSArray *results = [directoryContents filteredArrayUsingPredicate:predicate];  
  
//近似匹配字符串，类似SQL中的语法  
NSString *match = @"imagexyz*.png";  
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF like %@", match];  
    NSArray *results = [directoryContents filteredArrayUsingPredicate:predicate];  
//不区分大小写匹配  
NSString *match = @"imagexyz*.png";  
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF like[cd] %@", match];  
    NSArray *results = [directoryContents filteredArrayUsingPredicate:predicate];  
//正则匹配  
NSString *match = @"imagexyz-\d{3}\.png";  
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF matches %@", match];  
    NSArray *results = [directoryContents filteredArrayUsingPredicate:predicate];