NSPredicate

最新推荐文章于 2024-08-17 19:58:30 发布

bddzz

最新推荐文章于 2024-08-17 19:58:30 发布

阅读量280

点赞数

CC 4.0 BY-SA版权

文章标签： NSPredicate

本文链接：https://blog.youkuaiyun.com/bddzzw/article/details/49560743

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。

定义(最常用到的方法)：

1 NSPredicate *ca = [NSPredicate predicateWithFormat:(NSString *), ...];

Format：

(1)比较运算符>,<,==,>=,<=,!=

可用于数值及字符串

例：@"number > 100"

(2)范围运算符：IN、BETWEEN

例：@"number BETWEEN {1,5}"

@"address IN {'shanghai','beijing'}"

(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：

(1)对NSArray进行过滤

1 NSArray *array = [[NSArray alloc]initWithObjects:@"beijing",@"shanghai",@"guangzou",@"wuhan", nil];

2 NSString *string = @"ang";

3 NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",string];

4 NSLog(@"%@",[array filteredArrayUsingPredicate:pred]);

(2)判断字符串首字母是否为字母:

1 NSString *regex = @"[A-Za-z]+";

2 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

4 if ([predicate evaluateWithObject:aString]) {

5 }

(3)字符串替换：

1 NSError* error = NULL;

2 NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:@"(encoding=\")[^\"]+(\")" options:0 error:&error];

3 NSString* sample = @"<xml encoding=\"abc\"></xml><xml encoding=\"def\"></xml><xml encoding=\"ttt\"></xml>";

4 NSLog(@"Start:%@",sample);

5 NSString* result = [regex stringByReplacingMatchesInString:sample

6 options:0 range:NSMakeRange(0, sample.length)

7 withTemplate:@"$1utf-8$2"];

8 NSLog(@"Result:%@", result);

(4)截取字符串如下：

1 //组装一个字符串，需要把里面的网址解析出来

2 NSString *urlString=@"<meta/><link/><title>1Q84 BOOK1</title></head><body>";

4 //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

5 NSError *error;

7 //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

8 NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?<=title\\>).*(?=</title)" options:0 error:&error];

10 if (regex != nil) {

11 NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0 range:NSMakeRange(0, [urlString length])];

13 if (firstMatch) {

14 NSRange resultRange = [firstMatch rangeAtIndex:0];

16 //从urlString当中截取数据

17 NSString *result=[urlString substringWithRange:resultRange];

18 //输出结果

19 NSLog(@"->%@<-",result);

20 }

22 }

(5)判断手机号码，电话号码函数

1 // 正则判断手机号码地址格式

2 - (BOOL)isMobileNumber:(NSString *)mobileNum

3 {

4 /**

5 * 手机号码

6 * 移动：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188

7 * 联通：130,131,132,152,155,156,185,186

8 * 电信：133,1349,153,180,189

9 */

10 NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";

11 /**

12 10 * 中国移动：China Mobile

13 11 * 134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188

14 12 */

15 NSString * CM = @"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";

16 /**

17 15 * 中国联通：China Unicom

18 16 * 130,131,132,152,155,156,185,186

19 17 */

20 NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";

21 /**

22 20 * 中国电信：China Telecom

23 21 * 133,1349,153,180,189

24 22 */

25 NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";

26 /**

27 25 * 大陆地区固话及小灵通

28 26 * 区号：010,020,021,022,023,024,025,027,028,029

29 27 * 号码：七位或八位

30 28 */

31 // NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";

33 NSPredicate *regextestmobile = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", MOBILE];

34 NSPredicate *regextestcm = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CM];

35 NSPredicate *regextestcu = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CU];

36 NSPredicate *regextestct = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CT];

38 if (([regextestmobile evaluateWithObject:mobileNum] == YES)

39 || ([regextestcm evaluateWithObject:mobileNum] == YES)

40 || ([regextestct evaluateWithObject:mobileNum] == YES)

41 || ([regextestcu evaluateWithObject:mobileNum] == YES))

42 {

43 if([regextestcm evaluateWithObject:mobileNum] == YES) {

44 NSLog(@"China Mobile");

45 } else if([regextestct evaluateWithObject:mobileNum] == YES) {

46 NSLog(@"China Telecom");

47 } else if ([regextestcu evaluateWithObject:mobileNum] == YES) {

48 NSLog(@"China Unicom");

49 } else {

50 NSLog(@"Unknow");

51 }

53 return YES;

54 }

55 else

56 {

57 return NO;

58 }

59 }

(6)邮箱验证、电话号码验证:

1 //是否是有效的正则表达式

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

5 {

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

9 return [predicate evaluateWithObject:strDestination];

11 }

13 //验证email

14 +(BOOL)isValidateEmail:(NSString *)email {

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

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

20 return rt;

22 }

24 //验证电话号码

25 +(BOOL)isValidateTelNumber:(NSString *)number {

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

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

31 return rt;

33 }

(7)NSDate进行筛选

1 //日期在十天之内:

2 NSDate *endDate = [[NSDate date] retain];

3 NSTimeInterval timeInterval= [endDate timeIntervalSinceReferenceDate];

4 timeInterval -=3600*24*10;

5 NSDate *beginDate = [[NSDate dateWithTimeIntervalSinceReferenceDate:timeInterval] retain];

6 //对coredata进行筛选(假设有fetchRequest)

7 NSPredicate *predicate_date =

8 [NSPredicate predicateWithFormat:@"date >= %@ AND date <= %@", beginDate,endDate];

10 [fetchRequest setPredicate:predicate_date];

11 //释放retained的对象

12 [endDate release];

[beginDate release];