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 *), ...];
(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
2 NSString *regex = @"[A-Za-z]+";
3 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
4
5 if ([predicate evaluateWithObject:aString]) {
6 }
(3)字符串替换：
1 NSError* error = NULL; 2 NSRegularExpression* regex = [NSRegularExpression regularExpressionWithPattern:@"(encoding=\")[^\"]+(\")" 3 options:0 4 error:&error]; 5 NSString* sample = @"<xml encoding=\"abc\"></xml><xml encoding=\"def\"></xml><xml encoding=\"ttt\"></xml>"; 6 NSLog(@"Start:%@",sample); 7 NSString* result = [regex stringByReplacingMatchesInString:sample 8 options:0 9 range:NSMakeRange(0, sample.length) 10 withTemplate:@"$1utf-8$2"]; 11 NSLog(@"Result:%@", result);
(4)截取字符串如下：
1 //组装一个字符串，需要把里面的网址解析出来
2 NSString *urlString=@"<meta/><link/><title>1Q84 BOOK1</title></head><body>";
3
4 //NSRegularExpression类里面调用表达的方法需要传递一个NSError的参数。下面定义一个
5 NSError *error;
6
7 //http+:[^\\s]* 这个表达式是检测一个网址的。(?<=title\>).*(?=</title)截取html文章中的<title></title>中内文字的正则表达式
8 NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?<=title\\>).*(?=</title)" options:0 error:&error];
9
10 if (regex != nil) {
11 NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0 range:NSMakeRange(0, [urlString length])];
12
13 if (firstMatch) {
14 NSRange resultRange = [firstMatch rangeAtIndex:0];
15
16 //从urlString当中截取数据
17 NSString *result=[urlString substringWithRange:resultRange];
18 //输出结果
19 NSLog(@"->%@<-",result);
20 }
21
22 }
(5)判断手机号码，电话号码函数
1 // 正则判断手机号码地址格式
2 - (BOOL)isMobileNumber:(NSString *)mobileNum
3 {
4 /**
5 * 手机号码
6 * 移动：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
7 * 联通：130,131,132,152,155,156,185,186
8 * 电信：133,1349,153,180,189
9 */
10 NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
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}$";
26 /**
27 25 * 大陆地区固话及小灵通
28 26 * 区号：010,020,021,022,023,024,025,027,028,029
29 27 * 号码：七位或八位
30 28 */
31 // NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";
32
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];
37
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 }
52
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
2
3 +(BOOL)isValidateRegularExpression:(NSString *)strDestination byExpression:(NSString *)strExpression
4
5 {
6
7 NSPredicate *predicate = [NSPredicatepredicateWithFormat:@"SELF MATCHES %@", strExpression];
8
9 return [predicate evaluateWithObject:strDestination];
10
11 }
12
13 //验证email
14 +(BOOL)isValidateEmail:(NSString *)email {
15
16 NSString *strRegex = @"[A-Z0-9a-z._%+-][email protected][A-Za-z0-9.-]+\\.[A-Za-z]{1,5}";
17
18 BOOL rt = [CommonTools isValidateRegularExpression:email byExpression:strRegex];
19
20 return rt;
21
22 }
23
24 //验证电话号码
25 +(BOOL)isValidateTelNumber:(NSString *)number {
26
27 NSString *strRegex = @"[0-9]{1,20}";
28
29 BOOL rt = [CommonTools isValidateRegularExpression:number byExpression:strRegex];
30
31 return rt;
32
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]; 9 10 [fetchRequest setPredicate:predicate_date]; 11 //释放retained的对象 12 [endDate release]; 13 [beginDate release];
原文： http://blog.csdn.net/lianbaixue/article/details/10579117
时间： 2024-10-28 22:06:08