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NSPredicate用法总结(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)

2015-03-28 00:02 836 查看
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):

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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

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

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

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

if ([predicate evaluateWithObject:aString]) {

}

(3)字符串替换:

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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:

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//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);

}

}

(5)判断手机号码,电话号码函数

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// 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}$";

/**

* 中国移动:China Mobile

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

*/

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

/**

* 中国联通:China Unicom

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

*/

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

/**

* 中国电信:China Telecom

* 133,1349,153,180,189

*/

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

/**

* 大陆地区固话及小灵通

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

* 号码:七位或八位

*/

// 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;

}

}

(6)邮箱验证、电话号码验证:

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//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;

}

(7)NSDate进行筛选

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//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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