结合之前的学习笔记以及參考《Objective-C编程全解(第三版)》，对Objective-C知识点进行梳理总结。知识点一直在变，仅仅是作为參考，以苹果官方文档为准~
十八、谓语的使用及实例说明
首先先介绍基本经常使用的谓词：
（1）逻辑运算符 && AND || OR 都能够用
（2）IN包括
（3）模糊查询
a、以……开头 BEGINSWITH
b、以……结尾 ENDSWITH
c、包括….字符 CONTAINS
（4）用like进行模糊查询
通配符：*表示随意个字符 ？表示单个字符
like *a 以a结尾
like a* 以a开头
like *a* 包括a字符
like ?a* 第二个字符为a的字符串实例说明：
创建Book类，Book.h
@interface Book : NSObject
{
NSInteger _price;
NSString* _bookName;
}
- (instancetype)initWithPrice:(NSInteger)price andBookName:(NSString *)bookName;
@endBook.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);
// 逻辑运算符 和 IN
predicate = [NSPredicate predicateWithFormat:@"bookName IN {'C Programming','C++ Programming'} AND price > 30"];
filterArray = [books filteredArrayUsingPredicate:predicate];
NSLog(@"%@",filterArray);
// 模糊查询 和 用通配符查询
predicate = [NSPredicate predicateWithFormat:@"bookName CONTAINS 'guiding' || bookName like '*Program*' "]; //包括guiding或者包括Program
filterArray = [books filteredArrayUsingPredicate:predicate];
NSLog(@"%@",filterArray);
}
return 0;
}
output：
2015-07-09 20:17:24.403 exercise_谓语[632:9877] (
"Book price:32,named C++ Programming",
"Book price:45,named OC guiding"
)
2015-07-09 20:17:24.404 exercise_谓语[632:9877] (
"Book price:32,named C++ Programming"
)
2015-07-09 20:17:24.407 exercise_谓语[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"
)