一 問題描述

查找數(shù)組中是否包含指定

二 問題解決

方法一

    NSArray  *array =@[@"abc123", @"cde234" , @"fgh456", @"ijk567", @"KLm567", @"MnO890", @"opq012", @"Rst123"];
    //匹配字符串，反回結(jié)果， SELF＝＝表示數(shù)組中每一個元素
    NSString *match1 = @"MnO890";
    NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"SELF == %@", match1];
    NSArray *results1 = [array filteredArrayUsingPredicate:predicate1];
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方法二

[array enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        if ([obj isEqualToString:@"opq012"]) {
            NSLog(@"%@-索引%d",obj, (int)idx);
        }
    }];  
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三 拓展延伸

如何使用謂詞NSPredicate實現(xiàn)快速尋找。

先看下定義

NSPredicate *ca = [NSPredicate predicateWithFormat:(NSString *), ...];  
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說明：
Format：有如下幾種規(guī)則

(1)比較運算符>,<,==,>=,<=,!=
可用于數(shù)值及字符串
例：@"number > 100"

(2)范圍運算符：IN、BETWEEN
例：@"number BETWEEN {1,5}"
   @"address IN {'shanghai','beijing'}"

(3)字符串本身:SELF 
例：@“SELF == ‘APPLE’"

(4)字符串相關(guān)：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(jié)束
注:[c]不區(qū)分大小寫[d]不區(qū)分發(fā)音符號即沒有重音符號[cd]既不區(qū)分大小寫，也不區(qū)分發(fā)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(dá)式：MATCHES
例：NSString *regex = @"^A.+e$";   //以A開頭，e結(jié)尾
   @"name MATCHES %@",regex"
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具體使用方法如下

1.NSString對象

    NSArray  *array =@[@"abc123", @"cde234" , @"fgh456", @"ijk567", @"KLm567", @"MnO890", @"opq012", @"Rst123"];
    //匹配字符串，反回結(jié)果， SELF＝＝表示數(shù)組中每一個元素
    NSString *match1 = @"MnO890";
    NSPredicate *predicate1 = [NSPredicate predicateWithFormat:@"SELF == %@", match1];
    NSArray *results1 = [array filteredArrayUsingPredicate:predicate1];

    //近似匹配字符串，類似SQL中的語法
    NSString *match2 = @"fgh45";
    NSPredicate *predicate2 = [NSPredicate predicateWithFormat:@"SELF contains %@", match2];
    NSArray *results2 = [array filteredArrayUsingPredicate:predicate2];
    //不區(qū)分大小寫匹配
    NSString *match3 = @"klm567";
    NSPredicate *predicate3 = [NSPredicate predicateWithFormat:@"SELF like[cd] %@", match3];
    NSArray *results3 = [array filteredArrayUsingPredicate:predicate3];
    //正則匹配
    NSString *match4 = @"[a-zA-Z0-9]{6}";
    NSPredicate *predicate4 = [NSPredicate predicateWithFormat:@"SELF matches %@", match4];
    NSArray *results4 = [array filteredArrayUsingPredicate:predicate4];

    NSLog(@"%@\n%@\n%@\n%@\n",results1,results2,results3,results4);
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輸出結(jié)果

(
    MnO890
)
(
    fgh456
)
(
    KLm567
)
(
    abc123,
    cde234,
    fgh456,
    ijk567,
    KLm567,
    MnO890,
    opq012,
    Rst123
)
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2.含有屬性的對象

@interface Person: NSObject 
{
    NSString *_name;
    NSString *_telephone;
    NSInteger _id;
}

@property (nonatomic, copy) NSString *name;
@property (nonatomic, copy) NSString *telephone;
@property (nonatomic, assign) NSInteger id;

@end
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1）.等于查詢

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name == %@", "張三"]; 
NSArray *filteredArray = [array filteredArrayUsingPredicate:predicate];
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2）.模糊查詢

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name CONTAINS %@", @"A"]; //predicate只能是對象
NSArray *filteredArray = [array filteredArrayUsingPredicate:predicate];
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