Cocoa过滤器NSPredicate的完全用法

1. Cocoa用nspredicate描述查询的方式，原理类似于在数据库中进行查询
2. 计算谓词：
3. //基本的查询
4. nspredicate*predicate;
5. predicate=[nspredicatepredicateWithFormat:@"name=='Herbie'"];
6. BOOLmatch=[predicateevaluateWithObject:car];
7. NSLog(@"%s",(match)?"YES":"NO");
9. //在整个cars里面循环比较
10. predicate=[nspredicatepredicateWithFormat:@"engine.horsepower>150"];
11. NSArray*cars=[garagecars];
12. for(Car*carin[garagecars]){
13. if([predicateevaluateWithObject:car]){
14. NSLog(@"%@",car.name);
15. }
16. }
18. //输出完整的信息
19. predicate=[nspredicatepredicateWithFormat:@"engine.horsepower>150"];
20. NSArray*results;
21. results=[carsfilteredArrayUsingPredicate:predicate];
22. //含有变量的谓词
23. nspredicate*predicateTemplate=[nspredicatepredicateWithFormat:@"name==$NAME"];
24. NSDictionary*varDict;
25. varDict=[NSDictionarydictionaryWithObjectsAndKeys:
26. @"Herbie",@"NAME",nil];
27. predicate=[predicateTemplatepredicateWithSubstitutionVariables:varDict];
28. NSLog(@"SnorGLE:%@",predicate);
29. match=[predicateevaluateWithObject:car];
30. NSLog(@"%s",(match)?"YES":"NO");
31. //注意不能使用$VARIABLE作为路径名，因为它值代表值
32. //谓词字符窜还支持c语言中一些常用的运算符
33. predicate=[nspredicatepredicateWithFormat:
34. @"(engine.horsepower>50)AND(engine.horsepower<200)"];
35. results=[carsfilteredArrayUsingPredicate:predicate];
36. NSLog(@"oop%@",results);
37. predicate=[nspredicatepredicateWithFormat:@"name<'Newton'"];
38. NSLog(@"%@",[resultsvalueForKey:@"name"]);
39. //强大的数组运算符
40. @"engine.horsepowerBETWEEN{50,200}"];
41. NSArray*betweens=[NSArrayarrayWithObjects:
42. [NSNumbernumberWithInt:50],[NSNumbernumberWithInt:200],nil];
43. predicate=[nspredicatepredicateWithFormat:@"engine.horsepowerBETWEEN%@",betweens];
44. predicateTemplate=[nspredicatepredicateWithFormat:@"engine.horsepowerBETWEEN$POWERS"];
45. varDict=[NSDictionarydictionaryWithObjectsAndKeys:betweens,@"POWERS",nil];
46. predicate=[predicateTemplatepredicateWithSubstitutionVariables:varDict];
47. //IN运算符
48. predicate=[nspredicatepredicateWithFormat:@"nameIN{'Herbie','Snugs','Badger','Flap'}"];
49. predicate=[nspredicatepredicateWithFormat:@"SELF.nameIN{'Herbie','Flap'}"];
50. "name"]);
51. names=[carsvalueForKey:@"name"];
52. predicate=[nspredicatepredicateWithFormat:@"SELFIN{'Herbie',248)"> results=[namesfilteredArrayUsingPredicate:predicate];//这里限制了SELF的范围
53. //BEGINSWITH,ENDSWITH,CONTAINS
54. //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
55. predicate=[nspredicatepredicateWithFormat:@"nameBEGINSWITH'Bad'"];
56. predicate=[nspredicatepredicateWithFormat:@"nameBEGINSWITH'HERB'"];
57. predicate=[nspredicatepredicateWithFormat:@"nameBEGINSWITH[cd]'HERB'"];
58. //LIKE运算符（通配符）
59. predicate=[nspredicatepredicateWithFormat:@"nameLIKE[cd]'*er*'"];
60. predicate=[nspredicatepredicateWithFormat:@"nameLIKE[cd]'???er*'"];