Objective-C(十八、謂語使用及執行個體說明)——iOS開發基礎

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結合之前的學習筆記以及參考《Objective-C編程全解(第三版)》，對Objective-C知識點進行梳理總結。知識點一直在變，只是作為參考，以蘋果官方文檔為準~

十八、謂語的使用及執行個體說明

首先先介紹基本常用的謂詞：
（1）邏輯運算子 && AND || OR 都可以用
（2）IN包含
（3）模糊查詢
a、以……開頭 BEGINSWITH
b、以……結尾 ENDSWITH
c、包含….字元 CONTAINS
（4）用like進行模糊查詢
萬用字元：*表示任意個字元 ？表示單個字元

like *a  以a結尾like a*  以a開頭like *a* 包含a字元like ?a* 第二個字元為a的字串

執行個體說明：

建立Book類，Book.h

@interface Book : NSObject{    NSInteger _price;    NSString* _bookName;}- (instancetype)initWithPrice:(NSInteger)price andBookName:(NSString *)bookName;@end

Book.h

#import "Book.h"@implementation Book- (instancetype)initWithPrice:(NSInteger)price andBookName:(NSString *)bookName {    if (self = [super init]) {        _price = price;        _bookName = bookName;    }    return self;}- (NSString *)description {    return [NSString stringWithFormat:@"Book price:%li,named %@",_price,_bookName];}@end

main.m

int main(int argc, const char * argv[]) {    @autoreleasepool {        Book* book1 = [[Book alloc] initWithPrice:20 andBookName:@"C Programming"];        Book* book2 = [[Book alloc] initWithPrice:32 andBookName:@"C++ Programming"];        Book* book3 = [[Book alloc] initWithPrice:18 andBookName:@"Java Programming"];        Book* book4 = [[Book alloc] initWithPrice:45 andBookName:@"OC guiding"];        Book* book5 = [[Book alloc] initWithPrice:28 andBookName:@"iOS guiding"];        NSArray* books = [NSArray arrayWithObjects:book1,book2,book3,book4,book5, nil];        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"price > %i",30];        NSArray *filterArray = [books filteredArrayUsingPredicate:predicate];        NSLog(@"%@",filterArray);//      邏輯運算子 和 IN        predicate = [NSPredicate predicateWithFormat:@"bookName IN {‘C Programming‘,‘C++ Programming‘} AND price > 30"];        filterArray = [books filteredArrayUsingPredicate:predicate];        NSLog(@"%@",filterArray);//      模糊查詢 和 用萬用字元查詢        predicate = [NSPredicate predicateWithFormat:@"bookName CONTAINS ‘guiding‘ || bookName like ‘*Program*‘ "]; //包含guiding或者包含Program        filterArray = [books filteredArrayUsingPredicate:predicate];        NSLog(@"%@",filterArray);    }    return 0;}

output：

2015-07-09 20:17:24.403 exercise_謂語[632:9877] (    "Book price:32,named C++ Programming",    "Book price:45,named OC guiding")2015-07-09 20:17:24.404 exercise_謂語[632:9877] (    "Book price:32,named C++ Programming")2015-07-09 20:17:24.407 exercise_謂語[632:9877] (    "Book price:20,named C Programming",    "Book price:32,named C++ Programming",    "Book price:18,named Java Programming",    "Book price:45,named OC guiding",    "Book price:28,named iOS guiding")

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Objective-C(十八、謂語使用及執行個體說明)——iOS開發基礎