iOS的查询、过滤（NSPredicate）

原文：http://www.2cto.com/kf/201208/150608.html

参考：http://blog.csdn.net/iscape/article/details/7318021

参考：http://blog.csdn.net/zhulei1018/article/details/6777220

首先举一个例子：
匹配9-15个由字母/数字组成的字符串的正则表达式：
    NSString * regex = @"^[A-Za-z0-9]{9,15}$";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
    BOOL isMatch = [pred evaluateWithObject:txtfldPhoneNumber.text];

Cocoa用NSPredicate描述查询的方式，原理类似于在数据库中进行查询

用BETWEEN，IN，BEGINWITH，ENDWITH，CONTAINS，LIKE这些谓词来构造NSPredicate，必要的时候使用SELF直接对自己进行匹配

//基本的查询  
NSPredicate *predicate; 
predicate = [NSPredicate predicateWithFormat: @"name == 'Herbie'"]; 
    BOOL match = [predicate evaluateWithObject: car]; 
    NSLog (@"%s", (match) ? "YES" : "NO"); 
//在整个cars里面循环比较  
    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"]; 
    NSArray *cars = [garage cars]; 
    for (Car *car in [garage cars]) { 
        if ([predicate evaluateWithObject: car]) { 
            NSLog (@"%@", car.name); 
        } 
    } 
//输出完整的信息  
    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"]; 
    NSArray *results; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
//含有变量的谓词  
    NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"]; 
    NSDictionary *varDict; 
    varDict = [NSDictionary dictionaryWithObjectsAndKeys: 
               @"Herbie", @"NAME", nil]; 
    predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict]; 
    NSLog(@"SNORGLE: %@", predicate); 
    match = [predicate evaluateWithObject: car]; 
  NSLog (@"%s", (match) ? "YES" : "NO"); 
//注意不能使用$VARIABLE作为路径名，因为它值代表值  
//谓词字符窜还支持c语言中一些常用的运算符  
    
    predicate = [NSPredicate predicateWithFormat: 
                 @"(engine.horsepower > 50) AND (engine.horsepower < 200)"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"oop %@", results); 
    
    predicate = [NSPredicate predicateWithFormat: @"name < 'Newton'"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", [results valueForKey: @"name"]); 
//强大的数组运算符  
    predicate = [NSPredicate predicateWithFormat: 
                 @"engine.horsepower BETWEEN { 50, 200 }"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
    
    NSArray *betweens = [NSArray arrayWithObjects: 
                         [NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil]; 
    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
    predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"]; 
    varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil]; 
    predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
//IN运算符  
    predicate = [NSPredicate predicateWithFormat: @"name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", [results valueForKey: @"name"]); 
    predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", [results valueForKey: @"name"]); 
    
    names = [cars valueForKey: @"name"]; 
    predicate = [NSPredicate predicateWithFormat: @"SELF IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"]; 
    results = [names filteredArrayUsingPredicate: predicate];//这里限制了SELF的范围  
    NSLog (@"%@", results); 
//BEGINSWITH,ENDSWITH,CONTAINS  
//附加符号，[c],[d],[cd],c表示不区分大小写，d表示不区分发音字符，cd表示什么都不区分  
    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'Bad'"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
    
    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'HERB'"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
    
    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] 'HERB'"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
//LIKE运算符（通配符）  
    predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '*er*'"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 
    
    predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '???er*'"]; 
    results = [cars filteredArrayUsingPredicate: predicate]; 
    NSLog (@"%@", results); 

//基本的查询
NSPredicate *predicate;
predicate = [NSPredicate predicateWithFormat: @"name == 'Herbie'"];
    BOOL match = [predicate evaluateWithObject: car];
    NSLog (@"%s", (match) ? "YES" : "NO");
//在整个cars里面循环比较
    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
    NSArray *cars = [garage cars];
    for (Car *car in [garage cars]) {
        if ([predicate evaluateWithObject: car]) {
            NSLog (@"%@", car.name);
        }
    }
//输出完整的信息
    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower > 150"];
    NSArray *results;
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
//含有变量的谓词
    NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:@"name == $NAME"];
    NSDictionary *varDict;
    varDict = [NSDictionary dictionaryWithObjectsAndKeys:
               @"Herbie", @"NAME", nil];
    predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
    NSLog(@"SNORGLE: %@", predicate);
    match = [predicate evaluateWithObject: car];
  NSLog (@"%s", (match) ? "YES" : "NO");
//注意不能使用$VARIABLE作为路径名，因为它值代表值
//谓词字符窜还支持c语言中一些常用的运算符
  
    predicate = [NSPredicate predicateWithFormat:
                 @"(engine.horsepower > 50) AND (engine.horsepower < 200)"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"oop %@", results);
  
    predicate = [NSPredicate predicateWithFormat: @"name < 'Newton'"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", [results valueForKey: @"name"]);
//强大的数组运算符
    predicate = [NSPredicate predicateWithFormat:
                 @"engine.horsepower BETWEEN { 50, 200 }"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
  
    NSArray *betweens = [NSArray arrayWithObjects:
                         [NSNumber numberWithInt: 50], [NSNumber numberWithInt: 200], nil];
    predicate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN %@", betweens];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
    predicateTemplate = [NSPredicate predicateWithFormat: @"engine.horsepower BETWEEN $POWERS"];
    varDict = [NSDictionary dictionaryWithObjectsAndKeys: betweens, @"POWERS", nil];
    predicate = [predicateTemplate predicateWithSubstitutionVariables: varDict];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
//IN运算符
    predicate = [NSPredicate predicateWithFormat: @"name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", [results valueForKey: @"name"]);
    predicate = [NSPredicate predicateWithFormat: @"SELF.name IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", [results valueForKey: @"name"]);
  
    names = [cars valueForKey: @"name"];
    predicate = [NSPredicate predicateWithFormat: @"SELF IN { 'Herbie', 'Snugs', 'Badger', 'Flap' }"];
    results = [names filteredArrayUsingPredicate: predicate];//这里限制了SELF的范围
    NSLog (@"%@", results);
//BEGINSWITH,ENDSWITH,CONTAINS
//附加符号，[c],[d],[cd],c表示不区分大小写，d表示不区分发音字符，cd表示什么都不区分
    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'Bad'"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
  
    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH 'HERB'"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
  
    predicate = [NSPredicate predicateWithFormat: @"name BEGINSWITH[cd] 'HERB'"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
//LIKE运算符（通配符）
    predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '*er*'"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);
  
    predicate = [NSPredicate predicateWithFormat: @"name LIKE[cd] '???er*'"];
    results = [cars filteredArrayUsingPredicate: predicate];
    NSLog (@"%@", results);