blocks|key|13291|text|id+object+=+myArray[0];//+similar+to+[myArray+objectAtIndex:0]

if(![object+isEqual:[NSNull+null]])
{
++++//do+something+if+object+is+not+equals+to+[NSNull+null]
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|13292|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>id object = myArray[0];// similar to [myArray objectAtIndex:0]

if(![object isEqual:[NSNull null]])
{
 //do something if object is not equals to [NSNull null]
}
</code></pre>

blocks|key|229727|text|if+(myArray+!=+(id)[NSNull+null])|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|229728|或|unstyled|229729|if(![myArray+isKindOfClass:[NSNull+class]])+|229730|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>if (myArray != (id)[NSNull null])
</code></pre>

OR

<pre><code>if(![myArray isKindOfClass:[NSNull class]]) 
</code></pre>

blocks|key|13323|text|根据Toni的回答，我做了一个宏。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|13324|#define+isNSNull(value)+[value+isKindOfClass:[NSNull+class]]|code-block|syntax|javascript|13325|然后使用它|13326|if+(isNSNull(dict[@"key"]))+...|13327|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Building off of Toni's answer I made a macro.

<pre><code>#define isNSNull(value) [value isKindOfClass:[NSNull class]]
</code></pre>

Then to use it

<pre><code>if (isNSNull(dict[@"key"])) ...
</code></pre>

blocks|key|229796|text|哦，伙计们。这是一个简单的问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|229797|//+if+no+null+values+have+been+returned.
if+([myValue+class]+==+[NSNull+class])+{
++++myValue+=+nil;
}|code-block|syntax|javascript|229798|我相信还有更好的答案，但这个答案是有效的。|229799|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Awww, guys. This is an easy one.

<pre><code>// if no null values have been returned.
if ([myValue class] == [NSNull class]) {
 myValue = nil;
}
</code></pre>

I'm sure there are better answers, but this one works.

blocks|key|13434|text|您可以使用以下检查：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|13435|if+(myArray[0]+!=+[NSNull+null])+{
++++//+Do+your+thing+here
}|code-block|syntax|javascript|13436|原因可以在苹果的官方文档中找到：|13437|使用NSNull|13438|NSNull类定义了一个单例对象，用于在禁止将nil作为值的情况下表示空值(通常在集合对象中，如数组或字典)。|13439|NSNull+*nullValue+=+[NSNull+null];
NSArray+*arrayWithNull+=+@[nullValue];
NSLog(@"arrayWithNull:+%25@",+arrayWithNull);
//+Output:+"arrayWithNull:+(<null>)"|13440|重要的是要认识到，NSNull实例在语义上不同于NO或false-它们都表示逻辑值；NSNull实例表示缺少值。NSNull实例在语义上等同于nil，但是认识到它不等于nil也很重要。因此，要测试空对象值，必须进行直接的对象比较。|13441|id+aValue+=+[arrayWithNull+objectAtIndex:0];
if+(aValue+==+nil)+{
++++NSLog(@"equals+nil");
}
else+if+(aValue+==+[NSNull+null])+{
++++NSLog(@"equals+NSNull+instance");
++++if+([aValue+isEqual:nil])+{
++++++++NSLog(@"isEqual:nil");
++++}
}
//+Output:+"equals+NSNull+instance"|13442|摘自https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/NumbersandValues/Articles/Null.html|offset|length|13443|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/NumbersandValues/Articles/Null.html^0|0|0|0|0|0|0|0|0|2|32|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|16|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|17|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|18|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1C|8|@]|9|@$U|1D|V|1E|1|1F]]|A|$]]|$1|W|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|X|$Y|$5|Z|10|11|A|$12|13]]]]

You can use the following check:

<pre><code>if (myArray[0] != [NSNull null]) {
 // Do your thing here
}
</code></pre>

The reason for this can be found on Apple's official docs:

<h2>Using NSNull</h2>

The NSNull class defines a singleton object you use to represent null values in situations where nil is prohibited as a value (typically in a collection object such as an array or a dictionary).

<pre><code>NSNull *nullValue = [NSNull null];
NSArray *arrayWithNull = @[nullValue];
NSLog(@"arrayWithNull: %@", arrayWithNull);
// Output: "arrayWithNull: (&lt;null&gt;)"
</code></pre>

It is important to appreciate that the NSNull instance is semantically different from NO or false—these both represent a logical value; the NSNull instance represents the absence of a value. The NSNull instance is semantically equivalent to nil, however it is also important to appreciate that it is not equal to nil. To test for a null object value, you must therefore make a direct object comparison.

<pre><code>id aValue = [arrayWithNull objectAtIndex:0];
if (aValue == nil) {
 NSLog(@"equals nil");
}
else if (aValue == [NSNull null]) {
 NSLog(@"equals NSNull instance");
 if ([aValue isEqual:nil]) {
 NSLog(@"isEqual:nil");
 }
}
// Output: "equals NSNull instance"
</code></pre>

Taken from <a href="https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/NumbersandValues/Articles/Null.html" rel="nofollow noreferrer">https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/NumbersandValues/Articles/Null.html</a>

blocks|key|229853|text|已经给出了许多好的和有趣的答案，并且(几乎)所有的答案都有效。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|229854|只是为了完成(以及其中的乐趣)：|229855|NSNull+null被记录为返回一个单例。因此|229856|if+(ob+==+[NSNull+null])+{...}+|code-block|syntax|javascript|229857|也运行得很好。|229858|然而，由于这是一个例外，我不认为使用==来比较对象通常不是一个好主意。(如果我要检查您的代码，我肯定会对此进行评论)。|229859|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|T|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

A lot of good and interesting answers have been given already and (nealry) all of them work. 

Just for completion (and the fun of it): 

[NSNull null] is documented to return a singleton. Therefore 

<pre><code>if (ob == [NSNull null]) {...} 
</code></pre>

works fine too. 

However, as this is an exception I don't think that using == for comparing objects is a good idea in general. (If I'd review your code, I'd certainly comment on this).

blocks|key|13376|text|在Swift中(或从Objective-C桥接)，可以在可选参数数组中包含NSNull和nil。NSArray%25s只能包含对象，并且永远不会有nil，但可能有NSNull。但是，Any?类型的Swift数组可能包含nil。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|13377|let+myArray:+[Any?]+=+[nil,+NSNull()]+//+[nil,+{{NSObject}}],+or+[nil,+<null>]|code-block|syntax|javascript|13378|要检查NSNull，请使用is检查对象的类型。此过程与Swift数组和NSArray对象相同：|13379|for+obj+in+myArray+{
++++if+obj+is+NSNull+{
++++++++//+object+is+of+type+NSNull
++++}+else+{
++++++++//+object+is+not+of+type+NSNull
++++}
}|13380|还可以使用if+let或guard检查是否可以将对象强制转换为NSNull|13381|guard+let+_+=+obj+as?+NSNull+else+{
++++//+obj+is+not+NSNull
++++continue;
}|13382|或|13383|if+let+_+=+obj+as?+NSNull+{
++++//+obj+is+NSNull
}|13384|entityMap^0|11|6|18|3|1C|7|1Z|3|27|6|2H|4|2Z|3|0|0|3|6|D|2|Z|7|0|0|5|6|C|5|V|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]|$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|1L|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1M|8|@$9|1N|A|1O|B|C]|$9|1P|A|1Q|B|C]|$9|1R|A|1S|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1T|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1U|8|@]|D|@]|E|$]]|$1|U|3|V|5|H|7|1V|8|@]|D|@]|E|$I|J]]|$1|W|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]]|X|$]]

In Swift (or bridging from Objective-C), it is possible to have <code>NSNull</code> and <code>nil</code> in an array of optionals. <code>NSArray</code>s can only contain objects and will never have <code>nil</code>, but may have <code>NSNull</code>. A Swift array of <code>Any?</code> types may contain <code>nil</code>, however.

<pre><code>let myArray: [Any?] = [nil, NSNull()] // [nil, {{NSObject}}], or [nil, &lt;null&gt;]
</code></pre>

To check against <code>NSNull</code>, use <code>is</code> to check an object's type. This process is the same for Swift arrays and <code>NSArray</code> objects:

<pre><code>for obj in myArray {
 if obj is NSNull {
 // object is of type NSNull
 } else {
 // object is not of type NSNull
 }
}
</code></pre>

You can also use an <code>if let</code> or <code>guard</code> to check if your object can be casted to <code>NSNull</code>:

<pre><code>guard let _ = obj as? NSNull else {
 // obj is not NSNull
 continue;
}
</code></pre>

or

<pre><code>if let _ = obj as? NSNull {
 // obj is NSNull
}
</code></pre>

I am getting an array with null value. Please check the structure of my array below:

<pre><code> (
 "&lt; null&gt;"
 )
</code></pre>

When I'm trying to access index 0 its crashing because of

<pre><code>-[NSNull isEqualToString:]: unrecognized selector sent to instance 0x389cea70
</code></pre>

Currently its crashing because of that array with a crash log:

<pre><code> *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull isEqualToString:]: unrecognized selector sent to instance 0x389cea70'
*** First throw call stack:
(0x2d9fdf53 0x3820a6af 0x2da018e7 0x2da001d3 0x2d94f598 0x1dee57 0x1dfd31 0x302f598d 0x301a03e3 0x3052aeed 0x3016728b 0x301659d3 0x3019ec41 0x3019e5e7 0x30173a25 0x30172221 0x2d9c918b 0x2d9c865b 0x2d9c6e4f 0x2d931ce7 0x2d931acb 0x3262c283 0x301d3a41 0xabb71 0xabaf8)
libc++abi.dylib: terminating with uncaught exception of type NSException
</code></pre>

How can I check if an object in an NSArray is NSNull?

Objective-C

Swift

我得到了一个空值的数组。请检查下面我的数组的结构： ( "< null>" )当我试图访问索引0时，它崩溃了，因为-[NSNull isEqualToString:]: unrecognized selector sent to instance 0x389cea70目前它正在崩溃，因为该数组有崩溃日志： *** Terminating app due to uncaught excepti

问如何检查NSArray中的对象是否为NSNull？
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问如何检查NSArray中的对象是否为NSNull？EN

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问如何检查NSArray中的对象是否为NSNull？
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