NSPredicate 查询/搜索
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IOS NSPredicate 查询、搜索
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];
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