Cocoa过滤器NSPredicate的完全用法

从下面的各个例子中，可以体会到NSPredicate的强大的能力，作为正则表达式的核心类，确实优化了很多的字符串及其正则相关的操作的流程。使代码简洁，而强大！

Cocoa用NSPredicate描述查询的方式，原理类似于在数据库中进行查询计算谓词：//基本的查询NSPredicate *predicate;predicate = [NSPredicate predicateWithFormat: @"name == 'Herbie'"];    BOOL match = [predicate evaluateWithObject: car];    NSLog (@"%s", (match) ? "YES" : "NO");//在整个cars里面循环比较    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];    NSArray *cars = [garage cars];    for (Car *car in [garage cars]) {        if ([predicate evaluateWithObject: car]) {            NSLog (@"%@", car.name);        }    }//输出完整的信息    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];    NSArray *results;    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);//含有变量的谓词    NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"];    NSDictionary *varDict;    varDict = [NSDictionary dictionaryWithObjectsAndKeys:               @"Herbie", @"NAME", nil];    predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];    NSLog(@"SNORGLE: %@", predicate);    match = [predicate evaluateWithObject: car];  NSLog (@"%s", (match) ? "YES" : "NO");//注意不能使用$VARIABLE作为路径名，因为它值代表值//谓词字符窜还支持c语言中一些常用的运算符      predicate = [NSPredicate predicateWithFormat:                 @"(engine.horsepower > 50) AND (engine.horsepower < 200)"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"oop %@", results);       predicate = [NSPredicate predicateWithFormat: @"name < 'Newton'"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", [results valueForKey: @"name"]);//强大的数组运算符    predicate = [NSPredicate predicateWithFormat:                 @"engine.horsepower BETWEEN { 50, 200 }"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);       NSArray *betweens = [NSArray arrayWithObjects:                         [NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil];    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);    predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"];    varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil];    predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);//IN运算符    predicate = [NSPredicate predicateWithFormat: @"name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", [results valueForKey: @"name"]);    predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", [results valueForKey: @"name"]);       names = [cars valueForKey: @"name"];    predicate = [NSPredicate predicateWithFormat: @"SELF IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];    results = [names filteredArrayUsingPredicate: predicate];//这里限制了SELF的范围    NSLog (@"%@", results);//BEGINSWITH,ENDSWITH,CONTAINS//附加符号，[c],[d],[cd],c表示不区分大小写，d表示不区分发音字符，cd表示什么都不区分    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'Bad'"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);       predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'HERB'"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);       predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] 'HERB'"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);//LIKE运算符（通配符）    predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '*er*'"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);       predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '???er*'"];    results = [cars filteredArrayUsingPredicate: predicate];    NSLog (@"%@", results);

转自：有香烟没火柴的空间