iOS中NSPredicate的简单学习

1、常用创建方式

NSPredicate *predicate = [NSPredicate predicateWithFormat:@""];

2、Format：的格式

2.1 比较运算符 >,<,==,>=,<=,!=

// 说明：Person类要自己写，这里就不贴代码了

 Person *p1 = [[Person alloc] initWithName:@"test1" AndAge:12];

Person *p2 = [[Person alloc] initWithName:@"test2" AndAge:23];

Person *p3 = [[Person alloc] initWithName:@"test3" AndAge:101];

Person *p4 = [[Person alloc] initWithName:@"test4" AndAge:120];

NSArray *arr = @[p1,p2,p3,p4];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"age>100&&name=='test4'"];
// 注意这个语法里面字符串要用单引号

NSArray *result = [arr filteredArrayUsingPredicate:predicate];
// 打印输出结果
NSLog(@"%@",result);

2.2 范围运算符，in(则表示在后面的{}中是否包含)，between(在某个范围内，如：age between{15,25}等价于 15<=age<=25)

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"age between {15,25}"];
或者
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name in {'test1','test2'}"];

2.3 对象本身self 如@"self == 'apple'"（也可以是NSNumber）

 NSArray *arr = @[@"ss",@"dddd",@"apple"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self == 'apple'"];
// 注意这个语法里面字符串要用单引号

NSArray *result = [arr filteredArrayUsingPredicate:predicate];
// 打印输出结果：apple

2.4 字符串相关

：BEGINSWITH、ENDSWITH、CONTAINS
例：@"name CONTAINS[cd] 'ang'" //包含某个字符串
@"name BEGINSWITH[c] 'sh'" //以某个字符串开头
@"name ENDSWITH[d] 'ang'" //以某个字符串结束

NSArray *arr = @[@"yangjie",@"zhangsan",@"lisi"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self contains[cd] 'ng'"];

 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self beginswith[c] 'y'"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self endswith[d] 'i'"];


// 注意这个语法里面字符串要用单引号

NSArray *result = [arr filteredArrayUsingPredicate:predicate];
// 打印输出结果
NSLog(@"%@",result);

2.5通配符：LIKE

例：@"name LIKE[cd] 'er'" //代表通配符,Like也接受[cd].
@"name LIKE[cd] '???er'"

NSArray *arr = @[@"yangjie",@"zhangsan",@"lisi",@"ang",@"tangddd",@"fangxxx"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self like[cd] 'ang*'"];
// 注意这个语法里面字符串要用单引号

NSArray *result = [arr filteredArrayUsingPredicate:predicate];
// 打印输出结果
NSLog(@"%@",result);

2.6正则表达式：MATCHES

例：NSString *regex = @"^A.+e$"; //以A开头，e结尾
@"name MATCHES %@",regex