ios-Predicate介绍

作者: 命运建筑师fly | 来源:发表于2017-10-25 08:29 被阅读0次

/
/熟悉Predicate
//[self testPredicateDefinition];

//学习Predicate的比较功能
//[self testPredicateComparation];

//学习Predicate范围运算功能
//[self testPredicateRange];

//学习Predicate 与自身相比的功能
//[self testPredicateComparationToSelf];

//学习Predicate 字符串相关：BEGINSWITH、ENDSWITH、CONTAINS
//[self testPredicateRelateToNSString];

//学习Predicate 的通配
[self testPredicateWildcard];
}

#pragma mark Predicate 的通配
- (void)testPredicateWildcard{
/*
(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 *placeArray = [NSArray arrayWithObjects:@"Shanghai",@"Hangzhou",@"Beijing",@"Macao",@"Taishan", nil];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF like '*ai*' "];

NSArray *tempArray = [placeArray filteredArrayUsingPredicate:predicate];
[tempArray enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"obj == %@",obj);
}];

}

#pragma mark Predicate 字符串相关：BEGINSWITH、ENDSWITH、CONTAINS
- (void)testPredicateRelateToNSString{
/*
(4)字符串相关：BEGINSWITH、ENDSWITH、CONTAINS
例：@"name CONTAIN[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
注:[c]不区分大小写[d]不区分发音符号即没有重音符号[cd]既不区分大小写，也不区分发音符号。
*/
NSArray *placeArray = [NSArray arrayWithObjects:@"Shanghai",@"Hangzhou",@"Beijing",@"Macao",@"Taishan", nil];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF CONTAINS [cd] 'an' "];
// NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"SELF Beginswith [cd] 'sh' "];

NSArray *tempArray = [placeArray filteredArrayUsingPredicate:predicate];
[tempArray enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"obj == %@",obj);
}];

}

#pragma mark Predicate 与自身相比的功能
- (void)testPredicateComparationToSelf{
/*
(3)字符串本身:SELF
例：@“SELF == ‘APPLE’"
*/

NSArray *placeArray = [NSArray arrayWithObjects:@"Shanghai",@"Hangzhou",@"Beijing",@"Macao",@"Taishan", nil];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF == 'Beijing'"];
NSArray *tempArray = [placeArray filteredArrayUsingPredicate:predicate];
[tempArray enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"obj == %@",obj);
}];

}

#pragma mark Predicate范围运算功能
- (void)testPredicateRange{
/*
(2)范围运算符：IN、BETWEEN
例：@"number BETWEEN {1,5}"
@"address IN {'shanghai','beijing'}"
*/
NSArray *array = [NSArray arrayWithObjects:@1,@2,@3,@4,@5,@2,@6, nil];
//NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF in {2,5}"]; 找到 in 的意思是array中{2,5}的元素
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF BETWEEN {2,5}"];
NSArray *fliterArray = [array filteredArrayUsingPredicate:predicate];
[fliterArray enumerateObjectsWithOptions:NSEnumerationConcurrent usingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"fliterArray = %@",obj);
}];

}

#pragma mark 测试Predicate的比较功能
- (void)testPredicateComparation{
/*
(1)比较运算符>,<,==,>=,<=,!=
可用于数值及字符串
例：@"number > 100"
*/
NSArray *array = [NSArray arrayWithObjects:@1,@2,@3,@4,@5,@2,@6, nil];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF >4"];
NSArray *fliterArray = [array filteredArrayUsingPredicate:predicate];
[fliterArray enumerateObjectsWithOptions:NSEnumerationConcurrent usingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"fliterArray = %@",obj);
}];
}

#pragma mark 熟悉Predicate
- (void)testPredicateDefinition{
NSArray *array = [[NSArray alloc]initWithObjects:@"beijing",@"shanghai",@"guangzou",@"wuhan", nil];;
//表示在数组里面筛选还有@"be"的字符串
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",@"be"];
NSArray *temp = [array filteredArrayUsingPredicate:predicate];
[temp enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"temp = %@",obj);
}];

/***************************************************************/
//NSPredicate给我留下最深印象的是两个数组求交集的一个需求，如果按照一般写法，需要2个遍历，但NSArray提供了一个filterUsingPredicate的方法，用了NSPredicate，就可以不用遍历！
NSArray *array1 = [NSArray arrayWithObjects:@1,@2,@3,@5,@5,@6,@7, nil];
NSArray *array2 = [NSArray arrayWithObjects:@4,@5, nil];
// 表示筛选array1在array2中的元素!YES！其中SELF指向filteredArrayUsingPredicate的调用者。
/*测试方案：
NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"SELF in %@",array2];
NSArray *temp1 = [array1 filteredArrayUsingPredicate:predicate1];
结果：
2015-11-08 10:55:19.879 NSPredicateDemo[11595:166012] obj ==5
2015-11-08 10:55:19.879 NSPredicateDemo[11595:166012] obj ==5

NSPredicate *predicate2 = [NSPredicate predicateWithFormat:@"SELF in %@",array1];
NSArray *temp1 = [array2 filteredArrayUsingPredicate:predicate1];
结果：
2015-11-08 10:55:19.879 NSPredicateDemo[11595:166012] obj ==5

*/
NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"SELF in %@",array2];
NSArray *temp1 = [array1 filteredArrayUsingPredicate:predicate1];

[temp1 enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSLog(@"temp1 = %@",obj);
}];

/*
2015-11-08 10:55:19.879 NSPredicateDemo[11595:166012] obj ==5
2015-11-08 10:55:19.879 NSPredicateDemo[11595:166012] obj ==5
*/

}



NSPredicate *predicate = [NSPredicate predicateWithFormat:@"age > 20"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name > 'abc' && age > 10"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name > 'abc' OR age > 10"];

/
/根据账号找到对应的名字;
- (void)testPredicateDefinition:(NSMutableArray *)totalArray selectAccount:(NSString *)account withBlock:(void (^)(sswConversationModle *modle))block{

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"account=%@",account];
NSArray *temp = [totalArray filteredArrayUsingPredicate:predicate];
[temp enumerateObjectsUsingBlock:^(sswConversationModle *modle, NSUInteger idx, BOOL * _Nonnull stop) {
block(modle);
}];
}


/
/根据账号找到对应的名字;

- (void)getPredicateDefinition:(NSMutableArray *)totalArray selectAccount:(NSString *)account withBlock:(void (^)(sswConversationModle *modle))block{

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"account=%@",account];
    NSArray *temp = [totalArray filteredArrayUsingPredicate:predicate];
    [temp enumerateObjectsUsingBlock:^(sswConversationModle *modle, NSUInteger idx, BOOL * _Nonnull stop) {
        block(modle);
    }];
}

-(void)sortByBusinessId{
    
    //根据business_id 降序排列
    
    NSSortDescriptor* sortByA = [NSSortDescriptor sortDescriptorWithKey:@"business_id" ascending:NO];
    
    m_notice_list=[[NSMutableArray alloc]initWithArray:[m_notice_list sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortByA]]];
    
    
    
    if (m_notice_list.count > 0) {
        
        //最大ID
        
        NoticeModle* firstModle = m_notice_list[0];
        
        m_max_tag_id = firstModle.business_id;
        
        //最小ID
        
        NoticeModle* lastModle = m_notice_list[m_notice_list.count-1];
        
        m_min_tag_id = lastModle.business_id;
        
        NSUserDefaults* defaults= [NSUserDefaults standardUserDefaults];
        
        [defaults setValue:m_max_tag_id forKey:maxKey];
        
        [defaults setValue:m_min_tag_id forKey:minKey];
        
        [self saveToFile];
        
    }
    
}

实现搜索

(void)filterContentForSearchText:(NSString*)searchText{

//我这里把没有 文本时读取数据库 的情形都写在一起了
    if (searchText.length == 0 && [[TCRecondBase selectHistroySearchGames] count] > 0) {
        self.type = HistroyType;
        self.datasArry = [TCRecondBase selectHistroySearchGames];

    }else{
        self.type = SearchResultType;
    }
    //检测输入的是不是拼音
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",@"^[A-Za-z]*$"];
    NSMutableArray* resultArry = [NSMutableArray array];
//是拼音则匹配以输入的拼音开头的且不区分大小写的游戏名
    if ([predicate evaluateWithObject:searchText]) {

        NSPredicate *predict = [NSPredicate predicateWithFormat:@"SELF BEGINSWITH[cd] %@",searchText];
        NSArray* spallArry = [_allSpalls filteredArrayUsingPredicate:predict];
        for (NSString* str in spallArry) {

            NSInteger index = [_allSpalls indexOfObject:str];

            [resultArry addObject:[_allNames objectAtIndex:index]];
        }
//输入的是数字或者汉字 则匹配名字中包含输入字符的游戏名
    }else{ 
        NSPredicate *predict = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",searchText];
//或者使用 @"name LIKE[cd] '*%@*'"    //*代表通配符
        resultArry = [_allNames filteredArrayUsingPredicate:predict].mutableCopy;
    }
    self.searchResultArry = resultArry;
    [self.histroyTableView reloadData];
}
//NSPredicate功能很强大,更多谓词匹配语法自行百度NSPredicate的使用

使用谓词实现分组排序

   NSMutableSet *set = [NSMutableSet set];
            
            //利用set不重复的特性,得到有多少组,根据model中的exchangeShortTime字段
            [self.contacts enumerateObjectsUsingBlock:^(Contacts * _Nonnull item, NSUInteger idx, BOOL * _Nonnull stop) {
                [set addObject:item.shengxiao];
            }];
            
            /*此时，set里面已经存储了可以分为组数*/
            
            //接下来需要用到NSPredicate语法进行筛选
            __block NSMutableArray *arr = [NSMutableArray array];
            [set enumerateObjectsUsingBlock:^(NSString * _Nonnull zodiac, BOOL * _Nonnull stop) {
                NSPredicate *predicate = [NSPredicate predicateWithFormat:@"shengxiao = %@", zodiac];
                NSArray *tempArr = [NSArray arrayWithArray:[self.contacts filteredArrayUsingPredicate:predicate]];
                [arr addObject:tempArr];
            }];

1.NSString 对象  
  
NSArray  *array =@["123", @"234" , @"345"];  
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF contains [cd] %@", "2"];  
NSArray *filterdArray = [array filterdArrayUsingPredicate:predicate];  
NSLog(@"%@", filterdArray );  
//output : @"123", "234"  
  
2.含有属性的对象  
  
@interface Person: NSObject   
{  
    NSString *_name;  
    NSString *_telephone;  
    NSInteger _id;  
}  
  
@property (nonatomic, copy) NSString *name;  
@property (nonatomic, copy) NSString *telephone;  
@property (nonatomic, assign) NSInteger id;  
  
@end  
//  
  
1）.等于查询  
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name == %@", "Ansel"];   
NSArray *filteredArray = [array filteredArrayUsingPredicate:predicate];  
  
2）.模糊查询  
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name CONTAINS %@", @"A"]; //predicate只能是对象  
NSArray *filteredArray = [array filteredArrayUsingPredicate:predicate];

ios-Predicate介绍

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