NSPredicate类

NSPredicate类,指定过滤器的条件

// 设置谓词条件
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"age <= 28"];
for (Person *person in array)
{
    // 表示指定的对象是否满足谓词条件
    if ([predicate evaluateWithObject:person])
    {
        //NSLog(@"person name : %@", person.name);
    } 
}

// 返回一个符合谓词条件的数组
NSArray *newArray = [array filteredArrayUsingPredicate:predicate];

// 格式占位符号
NSPredicate *pre = [NSPredicate predicateWithFormat:@" age <= %d", 30];
NSArray *array2 = [array filteredArrayUsingPredicate:pre];


// 运算符号 的加入 谓词不区分大小 && AND || OR
NSPredicate *pre3 = [NSPredicate predicateWithFormat:@"name > 'bruse' && age < %d", 30];
NSArray *array4 = [array filteredArrayUsingPredicate:pre3];


// 关键字 注意字符串⼀一定要添加''
NSPredicate *pre4 = [NSPredicate predicateWithFormat:@"self.name IN {'rose', 'bruse'}"];
NSArray *array5 = [array filteredArrayUsingPredicate:pre4];

// BEGINSWITH 检查某个字是否以**开头
NSPredicate *pre5 = [NSPredicate predicateWithFormat:@"self.name BEGINSWITH 'J'"];
NSArray *array6 = [array filteredArrayUsingPredicate:pre5];

// ENDSWITH 检查某个字符是以**结尾
NSPredicate *pre6 = [NSPredicate predicateWithFormat:@"self.name endswith 'e'"];
NSArray *array7 = [array filteredArrayUsingPredicate:pre6];

// CONTAINS 检查包含某个字符
NSPredicate *pre8 = [NSPredicate predicateWithFormat:@"self.name CONTAINS '小'"];
NSArray *array8 = [array filteredArrayUsingPredicate:pre8];

// Like 检查包含某个字符
NSString *s = [NSString stringWithFormat:@"name like '*%@*'",@"a"];
NSPredicate *predicate = [NSPredicate predicateWithFormat:s];