簡述：Cocoa框架中的NSPredicate用于查詢，原理和用法都類似于SQL中的where，作用相當于數據庫的過濾取。
本文參考鏈接：https://blog.csdn.net/mqyeweiyang/article/details/89356497
一、創建NSPredicate實例常用方法：
+ (NSPredicate *)predicateWithFormat:(NSString *)predicateFormat, ...;
二、常用語法
1.比較運算符> 、< 、== 、 >= 、<= 、 !=
例：@"number >= 99"
2.范圍運算符：IN 、BETWEEN
例：@"number BETWEEN {1,5}"
@"address IN {'shanghai','nanjing'}"
***3.字符串本身:SELF ***
例：@"SELF == 'APPLE'"
4.字符串相關：BEGINSWITH、ENDSWITH、CONTAINS
例：@"name CONTAIN[cd] 'ang'" //包含某個字符串
@"name BEGINSWITH[c] 'sh'" //以某個字符串開頭
@"name ENDSWITH[d] 'ang'" //以某個字符串結束
注:[c]不區分大小寫 , [d]不區分發音符號即沒有重音符號 , [cd]既不區分大小寫，也不區分發音符號。
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.正則表達式：MATCHES
例：NSString *regex = @"^A.+e$"; //以A開頭，e結尾
@"name MATCHES %@",regex
三、實際應用
1、對NSArray進行過濾
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、判斷字符串首字母是否為字母
NSString *regex = @"[A-Za-z]+";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
if ([predicate evaluateWithObject:aString]) {
3、字符串替換
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$2"];
NSLog(@"Result:%@", result);
4、判斷手機號碼，電話號碼函數
// 正則判斷手機號碼地址格式
- (BOOL)isMobileNumber:(NSString *)mobileNum
{
/**
* 手機號碼
* 移動：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
* 聯通：130,131,132,152,155,156,185,186
* 電信：133,1349,153,180,189
*/
NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
/**
10 * 中國移動：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}$";
/**
15 * 中國聯通：China Unicom
16 * 130,131,132,152,155,156,185,186
17 */
NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";
/**
20 * 中國電信：China Telecom
21 * 133,1349,153,180,189
22 */
NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";
/**
25 * 大陸地區固話及小靈通
26 * 區號：010,020,021,022,023,024,025,027,028,029
27 * 號碼：七位或八位
28 */
// NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";
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;
}
}
5、郵箱驗證、電話號碼驗證
//是否是有效的正則表達式
+(BOOL)isValidateRegularExpression:(NSString *)strDestination byExpression:(NSString *)strExpression
{
NSPredicate *predicate = [NSPredicatepredicateWithFormat:@"SELF MATCHES %@", strExpression];
return [predicate evaluateWithObject:strDestination];
}
//驗證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;
}
//驗證電話號碼
+(BOOL)isValidateTelNumber:(NSString *)number {
NSString *strRegex = @"[0-9]{1,20}";
BOOL rt = [CommonTools isValidateRegularExpression:number byExpression:strRegex];
return rt;
}
6、實際應用:NSDate進行篩選
//日期在十天之內:
NSDate *endDate = [[NSDate date] retain];
NSTimeInterval timeInterval= [endDate timeIntervalSinceReferenceDate];
timeInterval -=3600*24*10;
NSDate *beginDate = [[NSDate dateWithTimeIntervalSinceReferenceDate:timeInterval] retain];
//對coredata進行篩選(假設有fetchRequest)
NSPredicate *predicate_date =
[NSPredicate predicateWithFormat:@"date >= %@ AND date <= %@", beginDate,endDate];
[fetchRequest setPredicate:predicate_date];
//釋放retained的對象
[endDate release];
[beginDate release];
