+ (NSPredicate *)predicateWithFormat:(NSString *)predicateFormat, ...;NSPredicate *predicate  = [NSPredicate predicateWithFormat:@"name == 'Herbie'"];//注意:如果谓词串中的文本块未被引用,则被看做是键路径,即需要用引号表明是字符串,单引号,双引号均可.键路径可以在后台包含许多强大的功能

@interface Person : NSObject
@property NSString *firstName;
@property NSString *lastName;
@property NSNumber *age;
@endNSArray *firstNames = @[ @"Alice", @"Bob", @"Charlie", @"Quentin" ];
NSArray *lastNames = @[ @"Smith", @"Jones", @"Smith", @"Alberts" ];
NSArray *ages = @[ @24, @27, @33, @31 ];NSMutableArray *people = [NSMutableArray array];
[firstNames enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {Person *person = [[Person alloc] init];person.firstName = firstNames[idx];person.lastName = lastNames[idx];person.age = ages[idx];[people addObject:person];
}];NSPredicate *bobPredicate = [NSPredicate predicateWithFormat:@"firstName = 'Bob'"];
NSPredicate *smithPredicate = [NSPredicate predicateWithFormat:@"lastName = %@", @"Smith"];
NSPredicate *thirtiesPredicate = [NSPredicate predicateWithFormat:@"age >= 30"];// ["Bob Jones"]
NSLog(@"Bobs: %@", [people filteredArrayUsingPredicate:bobPredicate]);// ["Alice Smith", "Charlie Smith"]
NSLog(@"Smiths: %@", [people filteredArrayUsingPredicate:smithPredicate]);// ["Charlie Smith", "Quentin Alberts"]
NSLog(@"30's: %@", [people filteredArrayUsingPredicate:thirtiesPredicate]);

NSPredicate *ageIs33Predicate = [NSPredicate predicateWithFormat:@"%K = %@", @"age", @33];
//为了简便，也写作：@"age = 33"
NSLog(@"Age 33: %@", [people filteredArrayUsingPredicate:ageIs33Predicate]);
//运行结果： ["Charlie Smith"]

NSPredicate *namesBeginningWithLetterPredicate = [NSPredicate predicateWithFormat:@"(firstName BEGINSWITH[cd] $letter) OR (lastName BEGINSWITH[cd] $letter)"];
//为了简便，也写作：@"(firstName BEGINSWITH[cd] 'A') OR (lastName BEGINSWITH[cd] 'A')"
NSLog(@"'A' Names: %@", [people filteredArrayUsingPredicate:[namesBeginningWithLetterPredicate predicateWithSubstitutionVariables:@{@"letter": @"A"}]]);
// 运行结果：["Alice Smith", "Quentin Alberts"]

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"number BETWEEN {1,5}"];

//name 均是对象的属性
[NSPredicate predicateWithFormat:@"name CONTAINS[cd] 'xxx'"]；   //包含某个(xxx)字符串
 [NSPredicate predicateWithFormat:@"name BEGINSWITH[c] 'xxx'"]；     //以某个字符串开头
    [NSPredicate predicateWithFormat:@"name ENDSWITH[d] 'xxx'"]；      //以某个字符串结束

[NSPredicate predicateWithFormat:@"name LIKE[cd] '*er*'"]；     //*代表通配符,Like也接受[cd].

[NSPredicate predicateWithFormat:@"name LIKE[cd] '???er*'"]； NSString *regex = @"^A.+e$";   //以A开头，e结尾
[NSPredicate predicateWithFormat: @"name MATCHES %@",regex]； 
     //在数组筛选中，如果我不想用任何实例方法,想筛选成员本身时，可以用self来代替
NSArray *array = @[@"jim", @"cook", @"jobs", @"APPLE"];
NSPredicate *pre = [NSPredicate predicateWithFormat:@"SELF == 'APPLE'"]；
NSLog(@"%@", [array filteredArrayUsingPredicate:pre]);

//对NSArray进行过滤
NSArray *array = [[NSArray alloc]initWithObjects:@"beijing",@"shanghai",@"guangzou",@"wuhan", nil];
NSString *string = @"ang";
NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",string];
NSLog(@"%@",[array filteredArrayUsingPredicate:pred]);  

NSArray *array = @[@"jim", @"cook", @"jobs", @"sdevm"];
NSPredicate *pre = [NSPredicate predicateWithFormat:@"length > 3"];//lenght就是对数组成员执行[xxxx lenght]然后判断返回的NSUInteger值是否大于3
NSLog(@"%@", [array filteredArrayUsingPredicate:pre]);
//结果：( cook, jobs, sdevm )//扩展到NSString其他方法又比如integerValue：
NSArray *array = @[@"2", @"3", @"4", @"5"];
NSPredicate *pre = [NSPredicate predicateWithFormat:@"integerValue >= %@", @3];
NSLog(@"%@", [array filteredArrayUsingPredicate:pre]);

NSArray *array = @[@"2", @"3", @"4", @"5"];
NSPredicate *pre = [NSPredicate predicateWithFormat:@"self CONTAINS %@", @3];
NSLog(@"%@", [array filteredArrayUsingPredicate:pre]);

NSPredicate *bobPredicate = [NSPredicate predicateWithFormat:@"firstName = 'Bob'"];// ["Bob Jones"]
NSLog(@"Bobs: %@", [people filteredArrayUsingPredicate:bobPredicate]);

　　 NSPredicate *pre1 = [NSPredicate predicateWithFormat:@"code >= %@", @3];NSPredicate *pre2 = [NSPredicate predicateWithFormat:@"code <= %@", @2];//以AND形式组合NSPredicate *pre = [NSCompoundPredicate andPredicateWithSubpredicates:@[pre1,pre2]];//以OR形式组合NSPredicate *pre = [NSCompoundPredicate orPredicateWithSubpredicates:@[pre1, pre2]];

    Test *test1 = [[Test alloc]init];test1.name = @"absr";test1.code = @1;NSPredicate *pres = [NSPredicate predicateWithFormat:@"code == %@", @2];BOOL match = [pres evaluateWithObject:test1];

    NSString *string=@"assdbfe";NSString *targetString=@"^a.+e$";NSPredicate *pres = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", targetString];BOOL match = [pres evaluateWithObject:string];

NSString *strRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{1,5}"; 

NSString *strRegex = @"[0-9]{1,20}";  

    //查询NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:entityName];//条件查询NSPredicate *predicate = [NSPredicate predicateWithFormat:@""];request.predicate = predicate;//执行查询NSArray *objectArray = [self.managedObjectContext executeFetchRequest:request error:nil];if (![objectArray count]) {NSLog(@"未找到符合条件的对象!");}return objectArray;

NSPredicate *shortNamePredicate = [NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) {return [[evaluatedObject firstName] length] <= 5;}];// ["Alice Smith", "Bob Jones"]
NSLog(@"Short Names: %@", [people filteredArrayUsingPredicate:shortNamePredicate]);