xcode 我如何检查特定的 NSString 是否存在于 NSArray 中？
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How might I check if a particular NSString is present in an NSArray?
提问by Ravi
How might I check if a particular NSString is presnet in an NSArray?
我如何检查特定的 NSString 是否是 NSArray 中的 presnet？
回答by Janak Nirmal
You can do it like,
你可以这样做，
NSArray* yourArray = [NSArray arrayWithObjects: @"Str1", @"Str2", @"Str3", nil];
if ( [yourArray containsObject: yourStringToFind] ) {
// do found
} else {
// do not found
}
回答by bryanmac
Iterating or containsObject are order n ways to find.
迭代或 containsObject 是 n 阶查找方法。
If you want constant time lookup, you can also maintain a hash table like NSSet or NSHashTable but that increases space but saves time.
如果您想要恒定时间查找，您还可以维护一个哈希表，如 NSSet 或 NSHashTable，但这会增加空间但节省时间。
NSArray* strings = [NSArray arrayWithObjects: @"one", @"two", @"three", nil];
NSSet *set = [NSSet setWithArray:strings];
NSString* stringToFind = @"two";
NSLog(@"array contains: %d", (int)[strings containsObject:stringToFind]);
NSLog(@"set contains: %d", (int)[set containsObject:stringToFind]);
回答by Steven Fisher
Depends on your needs. Either indexOfObjectif you care about equality (most likely), or indexOfObjectIdenticalToif you care it's actually the same object (i.e. same address).
取决于您的需求。无论是indexOfObject如果你关心平等（最有可能），或者indexOfObjectIdenticalTo如果你关心它实际上是相同的对象（即同一个地址）。
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