IOS中 NSPredicate 的使用

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。
本文参考链接:https://blog.csdn.net/mqyeweiyang/article/details/89356497


一、创建NSPredicate实例常用方法:

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

二、常用语法

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

三、实际应用

1、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]);  

2、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]) {  

3、字符串替换


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

4、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;
    }
}

5、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;
 
}
 

6、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];

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