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本文转自 http://blog.csdn.net/ztp800201/article/details/8116081
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):
- 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
- 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]) {
- }
- 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$2"];
- NSLog(@"Result:%@", result);
(4)截取字符串如下:
- NSString *urlString=@"<meta/><link/><title>1Q84 BOOK1</title></head><body>";
-
- NSError *error;
-
- NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?<=title\\>).*(?=</title)" options:0 error:&error];
-
- if (regex != nil) {
- NSTextCheckingResult *firstMatch=[regex firstMatchInString:urlString options:0 range:NSMakeRange(0, [urlString length])];
-
- if (firstMatch) {
- NSRange resultRange = [firstMatch rangeAtIndex:0];
-
-
- NSString *result=[urlString substringWithRange:resultRange];
-
- NSLog(@"->%@<-",result);
- }
-
- }
(5)判断手机号码,电话号码函数
- - (BOOL)isMobileNumber:(NSString *)mobileNum
- {
-
- NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
-
- NSString * CM = @"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";
-
- NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";
-
- NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";
-
-
-
- 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;
- }
- }
(6)邮箱验证、电话号码验证:
-
- +(BOOL)isValidateRegularExpression:(NSString *)strDestination byExpression:(NSString *)strExpression
-
- {
-
- NSPredicate *predicate = [NSPredicatepredicateWithFormat:@"SELF MATCHES %@", strExpression];
-
- return [predicate evaluateWithObject:strDestination];
-
- }
-
- +(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;
-
- }
-
- +(BOOL)isValidateTelNumber:(NSString *)number {
-
- NSString *strRegex = @"[0-9]{1,20}";
-
- BOOL rt = [CommonTools isValidateRegularExpression:number byExpression:strRegex];
- (7)NSDate进行筛选
- NSDate *endDate = [[NSDate date] retain];
- NSTimeInterval timeInterval= [endDate timeIntervalSinceReferenceDate];
- timeInterval -=3600*24*10;
- NSDate *beginDate = [[NSDate dateWithTimeIntervalSinceReferenceDate:timeInterval] retain];
- NSPredicate *predicate_date =
- [NSPredicate predicateWithFormat:@"date >= %@ AND date <= %@", beginDate,endDate];
-
- [fetchRequest setPredicate:predicate_date];
- [endDate release];
- [beginDate release];
iOS 正则表达式之---谓词
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原文地址:http://www.cnblogs.com/crazystonelxl/p/5545322.html