NSPredicate
- NSPredicate 是预测的意思，但我们常翻译成谓词。
- 使用NSPredicate可以定义模糊查找条件，根据一定的条件从一个数组中快速找出符合一定条件的元素对象。
- 可以直接搜索对象
- 可以使用 >,<,==,>=,<=,!=来进行判断数据
@interface Person : NSObject
@property (nonatomic, strong) NSString *name;
@property (nonatomic, assign) int age;
@end
self.array = [[NSMutableArray alloc]init];
for (int i = 0; i < 10; i++) {
Person *p = [[Person alloc] init];
p.name = [NSString stringWithFormat:@"Mr.chen %d", i];
p.age = i * 10;
[self.array addObject:p];
}
NSPredicate *perdicate = [NSPredicate predicateWithFormat:@"age>50"];
NSArray *arr = [self.array filteredArrayUsingPredicate:perdicate];
NSLog(@"%@",arr);
// 打印结果
(
"name:Mr.chen 6, age:60",
"name:Mr.chen 7, age:70",
"name:Mr.chen 8, age:80",
"name:Mr.chen 9, age:90"
)
NSArray *arr1 = @[@1, @2, @3, @43, @6, @60];
NSPredicate *perdicate = [NSPredicate predicateWithFormat:@"SELF == 6"];
NSArray *temp = [arr1 filteredArrayUsingPredicate:perdicate];
NSLog(@"%@", temp);
//打印结果
(
6
)
- 可以使用 SELF 关键字代表自己
- in: arr1 和 arr2的交集
NSArray *arr1 = @[@1, @2, @3, @43, @6];
NSArray *arr2 = @[@2, @6];
NSPredicate *perdicate = [NSPredicate predicateWithFormat:@"SELF in %@", arr2];
NSArray *temp = [arr1 filteredArrayUsingPredicate:perdicate];
NSLog(@"%@", temp);
// 打印结果
(
2,
6
)
- BETWEEN 获取一定范围的值
NSArray *arr1 = @[@1, @2, @3, @43, @6, @60];
NSPredicate *perdicate = [NSPredicate predicateWithFormat:@"SELF BETWEEN{1,20}"];
NSArray *temp = [arr1 filteredArrayUsingPredicate:perdicate];
NSLog(@"%@", temp);
// 打印结果
(
1,
2,
3,
6
)
- BEGINSWITH 以某个字符串开头
- ENDSWITH 以某个字符串结尾
- CONTAINS 是否包含某个字符串
NSArray *arr1 = @[@"zhang3", @"wang4", @"lihu"];
NSPredicate *perdicate = [NSPredicate predicateWithFormat:@"SELF BEGINSWITH[cd] 'z' "];
NSArray *temp = [arr1 filteredArrayUsingPredicate:perdicate];
NSLog(@"%@", temp);
// 打印结果
(
zhang3
)
- 还可以使用LIKE它后面可以写[cd]格式符号, * 表示通配符
NSArray *arr1 = @[@"zhang3", @"wang4", @"lihu"];
NSPredicate *perdicate = [NSPredicate predicateWithFormat:@"SELF LIKE[cd] '*n*' "];
NSArray *temp = [arr1 filteredArrayUsingPredicate:perdicate];
NSLog(@"%@", temp);
// 打印结果
(
zhang3,
wang4
)
可以使用数组、字典、Data
NSSortDescriptor
- NSSortDescriptor 我们可以用它来排序
self.array = [[NSMutableArray alloc]init];
for (int i = 0; i < 12; i++) {
Person *p = [[Person alloc] init];
p.name = [NSString stringWithFormat:@"Mr.chen %d", i];
if (i > 9) {
p.age = 20;
} else {
p.age = arc4random_uniform(100);
}
p.money = arc4random_uniform(1000000000) * arc4random_uniform(1000000000) / 9 / 7;
[self.array addObject:p];
}
NSLog(@"%@",self.array);
NSSortDescriptor *ageSD = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];
NSSortDescriptor *moneySD = [NSSortDescriptor sortDescriptorWithKey:@"money" ascending:NO];
NSArray *arr = [self.array sortedArrayUsingDescriptors:@[ageSD, moneySD]];
NSLog(@"%@",arr);
// 打印结果
self.array = (
"name : Mr.chen 0, age : 38 , money : 39527952.00",
"name : Mr.chen 1, age : 6 , money : 44344428.00",
"name : Mr.chen 2, age : 39 , money : 37546996.00",
"name : Mr.chen 3, age : 31 , money : 42419204.00",
"name : Mr.chen 4, age : 51 , money : 37637156.00",
"name : Mr.chen 5, age : 28 , money : 48236272.00",
"name : Mr.chen 6, age : 80 , money : 29929636.00",
"name : Mr.chen 7, age : 56 , money : 17334832.00",
"name : Mr.chen 8, age : 1 , money : 53353300.00",
"name : Mr.chen 9, age : 13 , money : 4750739.00",
"name : Mr.chen 10, age : 20 , money : 60696080.00",
"name : Mr.chen 11, age : 20 , money : 39092136.00"
)
arr = (
"name : Mr.chen 8, age : 1 , money : 53353300.00",
"name : Mr.chen 1, age : 6 , money : 44344428.00",
"name : Mr.chen 9, age : 13 , money : 4750739.00",
"name : Mr.chen 10, age : 20 , money : 60696080.00",
"name : Mr.chen 11, age : 20 , money : 39092136.00",
"name : Mr.chen 5, age : 28 , money : 48236272.00",
"name : Mr.chen 3, age : 31 , money : 42419204.00",
"name : Mr.chen 0, age : 38 , money : 39527952.00",
"name : Mr.chen 2, age : 39 , money : 37546996.00",
"name : Mr.chen 4, age : 51 , money : 37637156.00",
"name : Mr.chen 7, age : 56 , money : 17334832.00",
"name : Mr.chen 6, age : 80 , money : 29929636.00"
)
- [NSSortDescriptor sortDescriptorWithKey:@"money" ascending:NO] 直接用内方法创建
- ascending YES，为升序，NO 为降序
- 当两个一起用的时候以第一个为基础的如果有相同在排序第二个，以此类推
