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NSPredicate 查询/搜索

2024-08-18 20:11:34   223人阅读

简述：Cocoa框架中的NSPredicate用于查询，原理和用法都类似于SQL中的where，作用相当于数据库的过滤取。

最常用到的函数

+ (NSPredicate *)predicateWithFormat:(NSString *)predicateFormat, ...;

1.比较运算符 > 、< 、== 、 >= 、<= 、 !=
例：@"number >= 99"

 

2.范围运算符：IN 、BETWEEN
例：@"number BETWEEN {1,5}"
      @"address IN {‘shanghai‘,‘nanjing‘}"

3.字符串本身:SELF 
例：@"SELF == ‘APPLE‘"

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。

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

 

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

 

实际应用:对NSArray进行过滤

NSArray *array = [[NSArray alloc]initWithObjects:@"beijing",@"shanghai",@"guangzou",@"wuhan", nil];  
NSString *string = @"ang";  
NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",string];  
NSLog(@"%@",[array filteredArrayUsingPredicate:pred]);

 

实际应用:判断字符串首字母是否为字母

NSString *regex = @"[A-Za-z]+";  
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];  
  
if ([predicate evaluateWithObject:aString]) {  
}

 

实际应用:字符串替换

NSError* error = NULL;  
NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:@"(encoding=\")[^\"]+(\")"  
                                                                            options:0  
                                                                            error:&error];  
NSString* sample = @"<xml encoding=\"abc\"></xml><xml encoding=\"def\"></xml><xml encoding=\"ttt\"></xml>";  
NSLog(@"Start:%@",sample);  
NSString* result = [regex stringByReplacingMatchesInString:sample  
                                                      options:0  
                                                       range:NSMakeRange(0, sample.length)  
                                                      withTemplate:@"$1utf-8$2"];  
NSLog(@"Result:%@", result);

 

实际应用:截取字符串

//组装一个字符串，需要把里面的网址解析出来  
NSString *urlString=@"<meta/><link/><title>1Q84 BOOK1</title></head><body>";  
  
//NSRegularExpression类里面调用表达的方法需要传递一个NSError的参数。下面定义一个    
NSError *error;  
  
//http+:[^\\s]* 这个表达式是检测一个网址的。(?<=title\>).*(?=</title)截取html文章中的<title></title>中内文字的正则表达式  
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?<=title\\>).*(?=</title)" options:0 error:&error];  
  
if (regex != nil) {  
    NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0 range:NSMakeRange(0, [urlString length])];  
      
    if (firstMatch) {  
        NSRange resultRange = [firstMatch rangeAtIndex:0];  
          
        //从urlString当中截取数据  
        NSString *result=[urlString substringWithRange:resultRange];  
        //输出结果  
        NSLog(@"->%@<-",result);  
    }  
      
}

 

实际应用:判断手机号码，电话号码函数

// 正则判断手机号码地址格式
- (BOOL)isMobileNumber:(NSString *)mobileNum
{
       /**
        * 手机号码
        * 移动：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
        * 联通：130,131,132,152,155,156,185,186
        * 电信：133,1349,153,180,189
        */
       NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
       /**
        10         * 中国移动：China Mobile
        11         * 134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
        12         */
       NSString * CM = @"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";
       /**
        15         * 中国联通：China Unicom
        16         * 130,131,132,152,155,156,185,186
        17         */
       NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";
       /**
        20         * 中国电信：China Telecom
        21         * 133,1349,153,180,189
        22         */
       NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";
       /**
        25         * 大陆地区固话及小灵通
        26         * 区号：010,020,021,022,023,024,025,027,028,029
        27         * 号码：七位或八位
        28         */
      // NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";
    
     NSPredicate *regextestmobile = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", MOBILE];
     NSPredicate *regextestcm = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CM];
     NSPredicate *regextestcu = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CU];
     NSPredicate *regextestct = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CT];
    
    if (([regextestmobile evaluateWithObject:mobileNum] == YES)
    || ([regextestcm evaluateWithObject:mobileNum] == YES)
    || ([regextestct evaluateWithObject:mobileNum] == YES)
    || ([regextestcu evaluateWithObject:mobileNum] == YES))
    {
        if([regextestcm evaluateWithObject:mobileNum] == YES) {
          NSLog(@"China Mobile");
        } else if([regextestct evaluateWithObject:mobileNum] == YES) {
          NSLog(@"China Telecom");
        } else if ([regextestcu evaluateWithObject:mobileNum] == YES) {
          NSLog(@"China Unicom");
        } else {
          NSLog(@"Unknow");
        }
        
        return YES;
    }
    else 
    {
        return NO;
    }
}

 

实际应用:邮箱验证、电话号码验证

//是否是有效的正则表达式

+(BOOL)isValidateRegularExpression:(NSString *)strDestination byExpression:(NSString *)strExpression

{

   NSPredicate *predicate = [NSPredicatepredicateWithFormat:@"SELF MATCHES %@", strExpression];  

   return [predicate evaluateWithObject:strDestination];

}

//验证email
+(BOOL)isValidateEmail:(NSString *)email {

   NSString *strRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{1,5}";

   BOOL rt = [CommonTools isValidateRegularExpression:email byExpression:strRegex];

   return rt;

}

//验证电话号码
+(BOOL)isValidateTelNumber:(NSString *)number {

   NSString *strRegex = @"[0-9]{1,20}";

   BOOL rt = [CommonTools isValidateRegularExpression:number byExpression:strRegex];

   return rt;

}

 

实际应用:NSDate进行筛选

//日期在十天之内:
NSDate *endDate = [[NSDate date] retain];
NSTimeInterval timeInterval= [endDate timeIntervalSinceReferenceDate];
timeInterval -=3600*24*10;
NSDate *beginDate = [[NSDate dateWithTimeIntervalSinceReferenceDate:timeInterval] retain];
//对coredata进行筛选(假设有fetchRequest)
NSPredicate *predicate_date =
[NSPredicate predicateWithFormat:@"date >= %@ AND date <= %@", beginDate,endDate];
    
[fetchRequest setPredicate:predicate_date];
//释放retained的对象
[endDate release];
[beginDate release];

NSPredicate 查询/搜索


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