iOS中NSArray的高级应用－过滤

NSArray可以用NSPredicate来过滤数组内容，代码：

//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];