blocks|key|1794390|text|NSString+*string+=+@"hello+bla+bla";
if+([string+rangeOfString:@"bla"].location+==+NSNotFound)+{
++NSLog(@"string+does+not+contain+bla");
}+else+{
++NSLog(@"string+contains+bla!");
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1794391|关键是注意到rangeOfString:返回一个NSRange结构，如果"haystack“不包含”{NSNotFound,+0}“，则the+documentation+says返回结构{NSNotFound,+0}。|unstyled|offset|length|style|CODE|1794392|1794393|如果你使用的是iOS+8或OS+X+Yosemite，你现在可以这样做：(*注意:如果在iOS7设备上调用这段代码，这将使你的应用崩溃)。|BOLD|1794394|NSString+*string+=+@"hello+bla+blah";
if+([string+containsString:@"bla"])+{
++NSLog(@"string+contains+bla!");
}+else+{
++NSLog(@"string+does+not+contain+bla");
}|1794395|(这也是它在Swift中的工作方式)|1794396|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/documentation/foundation/nsstring/1410144-rangeofstring?language=objc^0|0|6|E|O|7|1E|F|2M|F|1W|M|0|0|0|10|X|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|11|8|@$G|12|H|13|I|J]|$G|14|H|15|I|J]|$G|16|H|17|I|J]|$G|18|H|19|I|J]]|9|@$G|1A|H|1B|1|1C]]|A|$]]|$1|K|3|-4|5|F|7|1D|8|@]|9|@]|A|$]]|$1|L|3|M|5|F|7|1E|8|@$G|1F|H|1G|I|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1H|8|@]|9|@]|A|$B|C]]|$1|Q|3|R|5|F|7|1I|8|@]|9|@]|A|$]]|$1|S|3|-4|5|F|7|1J|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

<pre><code>NSString *string = @"hello bla bla";
if ([string rangeOfString:@"bla"].location == NSNotFound) {
 NSLog(@"string does not contain bla");
} else {
 NSLog(@"string contains bla!");
}
</code></pre>

The key is noticing that <code>rangeOfString:</code> returns an <code>NSRange</code> struct, and <a href="https://developer.apple.com/documentation/foundation/nsstring/1410144-rangeofstring?language=objc" rel="noreferrer">the documentation says</a> that it returns the struct <code>{NSNotFound, 0}</code> if the "haystack" does not contain the "needle".

<hr>

And if you're on iOS 8 or OS X Yosemite, you can now do: (*NOTE: This WILL crash your app if this code is called on an iOS7 device).

<pre><code>NSString *string = @"hello bla blah";
if ([string containsString:@"bla"]) {
 NSLog(@"string contains bla!");
} else {
 NSLog(@"string does not contain bla");
}
</code></pre>

(This is also how it would work in Swift)

blocks|key|1794420|text|对于iOS+8.0%2B和macOS+10.10%2B，您可以使用NSString的原生containsString:。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1794421|对于旧版本的iOS和macOS，您可以为NSString创建自己的(过时的)类别：|1794422|@interface+NSString+(+SubstringSearch+)
++++-+(BOOL)containsString:(NSString+*)substring;
@end

//+-+-+-+-+

@implementation+NSString+(+SubstringSearch+)

-+(BOOL)containsString:(NSString+*)substring
{++++
++++NSRange+range+=+[self+rangeOfString+:+substring];
++++BOOL+found+=+(+range.location+!=+NSNotFound+);
++++return+found;
}

@end|code-block|syntax|javascript|1794423|注意:请注意下面Daniel+Galasko关于命名的评论|BOLD|1794424|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/documentation/foundation/nsstring/1414563-containsstring?language=objc^0|14|F|14|F|0|0|0|0|0|Q|0^^$0|@$1|2|3|4|5|6|7|X|8|@$9|Y|A|Z|B|C]]|D|@$9|10|A|11|1|12]]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@$9|16|A|17|B|O]]|D|@]|E|$]]|$1|P|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|Q|$R|$5|S|T|U|E|$V|W]]]]

For iOS 8.0+ and macOS 10.10+, you can use NSString's native <a href="https://developer.apple.com/documentation/foundation/nsstring/1414563-containsstring?language=objc" rel="noreferrer"><code>containsString:</code></a>.

For older versions of iOS and macOS, you can create your own (obsolete) category for NSString:

<pre><code>@interface NSString ( SubstringSearch )
 - (BOOL)containsString:(NSString *)substring;
@end

// - - - - 

@implementation NSString ( SubstringSearch )

- (BOOL)containsString:(NSString *)substring
{ 
 NSRange range = [self rangeOfString : substring];
 BOOL found = ( range.location != NSNotFound );
 return found;
}

@end
</code></pre>

Note: Observe Daniel Galasko's comment below regarding naming

blocks|key|3202829|text|NSString+*myString+=+@"hello+bla+bla";
NSRange+rangeValue+=+[myString+rangeOfString:@"hello"+options:NSCaseInsensitiveSearch];

if+(rangeValue.length+>+0)
{
++++NSLog(@"string+contains+hello");
}+
else+
{
++++NSLog(@"string+does+not+contain+hello!");
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3202830|//您也可以使用以下命令：|unstyled|3202831|if+(rangeValue.location+==+NSNotFound)+
{
++++NSLog(@"string+does+not+contain+hello");
}+
else+
{
++++NSLog(@"string+contains+hello!");
}|3202832|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>NSString *myString = @"hello bla bla";
NSRange rangeValue = [myString rangeOfString:@"hello" options:NSCaseInsensitiveSearch];

if (rangeValue.length &gt; 0)
{
 NSLog(@"string contains hello");
} 
else 
{
 NSLog(@"string does not contain hello!");
}
</code></pre>

//You can alternatively use following too :

<pre><code>if (rangeValue.location == NSNotFound) 
{
 NSLog(@"string does not contain hello");
} 
else 
{
 NSLog(@"string contains hello!");
}
</code></pre>

blocks|key|1794468|text|Oneliner+(较少的代码量。DRY，因为您只有一个NSLog)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1794469|NSString+*string+=+@"hello+bla+bla";
NSLog(@"String+%25@",+([string+rangeOfString:@"bla"].location+==+NSNotFound)+?+@"not+found"+:+@"cotains+bla");+|code-block|syntax|javascript|1794470|entityMap^0|S|5|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Oneliner (Smaller amount of code. DRY, as you have only one <code>NSLog</code>): 


<pre><code>NSString *string = @"hello bla bla";
NSLog(@"String %@", ([string rangeOfString:@"bla"].location == NSNotFound) ? @"not found" : @"cotains bla"); 
</code></pre>

blocks|key|1161706|text|'s+solution的一个改进版本是NSString上的一个类别，它不仅可以判断一个字符串是否在另一个字符串中找到，还可以通过引用获取一个范围，它是：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1161707|@interface+NSString+(Contains)
-(BOOL)containsString:+(NSString*)substring
++++++++++++++atRange:(NSRange*)range;

-(BOOL)containsString:(NSString+*)substring;
@end

@implementation+NSString+(Contains)

-(BOOL)containsString:(NSString+*)substring
++++++++++++++atRange:(NSRange+*)range{

++++NSRange+r+=+[self+rangeOfString+:+substring];
++++BOOL+found+=+(+r.location+!=+NSNotFound+);
++++if+(range+!=+NULL)+*range+=+r;
++++return+found;
}

-(BOOL)containsString:(NSString+*)substring
{
++++return+[self+containsString:substring
++++++++++++++++++++++++atRange:NULL];
}

@end|code-block|syntax|javascript|1161708|像这样使用它：|1161709|NSString+*string+=+@"Hello,+World!";

//If+you+only+want+to+ensure+a+string+contains+a+certain+substring
if+([string+containsString:@"ello"+atRange:NULL])+{
++++NSLog(@"YES");
}

//+Or+simply
if+([string+containsString:@"ello"])+{
++++NSLog(@"YES");
}

//If+you+also+want+to+know+substring's+range
NSRange+range;
if+([string+containsString:@"ello"+atRange:&range])+{
++++NSLog(@"%25@",+NSStringFromRange(range));
}|1161710|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/2753956/how-do-i-check-if-a-string-contains-another-string-in-objective-c/6632346#6632346^0|0|B|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

An improved version of <a href="https://stackoverflow.com/questions/2753956/how-do-i-check-if-a-string-contains-another-string-in-objective-c/6632346#6632346">P i's solution</a>, a category on NSString, that not only will tell, if a string is found within another string, but also takes a range by reference, is:

<pre><code>@interface NSString (Contains)
-(BOOL)containsString: (NSString*)substring
 atRange:(NSRange*)range;

-(BOOL)containsString:(NSString *)substring;
@end

@implementation NSString (Contains)

-(BOOL)containsString:(NSString *)substring
 atRange:(NSRange *)range{

 NSRange r = [self rangeOfString : substring];
 BOOL found = ( r.location != NSNotFound );
 if (range != NULL) *range = r;
 return found;
}

-(BOOL)containsString:(NSString *)substring
{
 return [self containsString:substring
 atRange:NULL];
}

@end
</code></pre>

Use it like:

<pre><code>NSString *string = @"Hello, World!";

//If you only want to ensure a string contains a certain substring
if ([string containsString:@"ello" atRange:NULL]) {
 NSLog(@"YES");
}

// Or simply
if ([string containsString:@"ello"]) {
 NSLog(@"YES");
}

//If you also want to know substring's range
NSRange range;
if ([string containsString:@"ello" atRange:&amp;range]) {
 NSLog(@"%@", NSStringFromRange(range));
}
</code></pre>

blocks|key|1161720|text|下面是一个复制粘贴函数的代码片段：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1161721|-(BOOL)Contains:(NSString+*)StrSearchTerm+on:(NSString+*)StrText
{
++++return+[StrText+rangeOfString:StrSearchTerm+
++++++++options:NSCaseInsensitiveSearch].location+!=+NSNotFound;
}|code-block|syntax|javascript|1161722|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a copy-and-paste function snippet:

<pre><code>-(BOOL)Contains:(NSString *)StrSearchTerm on:(NSString *)StrText
{
 return [StrText rangeOfString:StrSearchTerm 
 options:NSCaseInsensitiveSearch].location != NSNotFound;
}
</code></pre>

blocks|key|3202939|text|由于这在Google中似乎是一个高排名的结果，我想补充一下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3202940|iOS+8和OS+X+10.10将containsString:方法添加到NSString中。针对这些系统的Dave+DeLong示例的更新版本：|offset|length|style|CODE|3202941|NSString+*string+=+@"hello+bla+bla";
if+([string+containsString:@"bla"])+{
++++NSLog(@"string+contains+bla!");
}+else+{
++++NSLog(@"string+does+not+contain+bla");
}|code-block|syntax|javascript|3202942|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/documentation/foundation/nsstring/1414563-containsstring?language=objc^0|0|H|F|11|8|H|F|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@$D|W|E|X|F|G]|$D|Y|E|Z|F|G]]|9|@$D|10|E|11|1|12]]|A|$]]|$1|H|3|I|5|J|7|13|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

Since this seems to be a high-ranking result in Google, I want to add this:

iOS 8 and OS X 10.10 add the <a href="https://developer.apple.com/documentation/foundation/nsstring/1414563-containsstring?language=objc" rel="noreferrer"><code>containsString:</code></a> method to <code>NSString</code>. An updated version of Dave DeLong's example for those systems:

<pre><code>NSString *string = @"hello bla bla";
if ([string containsString:@"bla"]) {
 NSLog(@"string contains bla!");
} else {
 NSLog(@"string does not contain bla");
}
</code></pre>

blocks|key|416536|text|通过iOS+8和Swift，我们可以使用localizedCaseInsensitiveContainsString方法|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|416537|+let+string:+NSString+=+"Café"
+let+substring:+NSString+=+"É"

+string.localizedCaseInsensitiveContainsString(substring)+//+true|code-block|syntax|javascript|416538|entityMap^0|2|5|8|5|K|12|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|D]]|E|@]|F|$]]|$1|G|3|H|5|I|7|U|8|@]|E|@]|F|$J|K]]|$1|L|3|-4|5|6|7|V|8|@]|E|@]|F|$]]]|M|$]]

With iOS 8 and Swift, we can use <code>localizedCaseInsensitiveContainsString</code> method 

<pre><code> let string: NSString = "Café"
 let substring: NSString = "É"

 string.localizedCaseInsensitiveContainsString(substring) // true
</code></pre>

blocks|key|1794612|text|如果你需要这样写一次：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1794613|NSString+*stringToSearchThrough+=+@"-rangeOfString+method+finds+and+returns+the+range+of+the+first+occurrence+of+a+given+string+within+the+receiver.";
BOOL+contains+=+[stringToSearchThrough+rangeOfString:@"occurence+of+a+given+string"].location+!=+NSNotFound;|code-block|syntax|javascript|1794614|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you need this once write:

<pre><code>NSString *stringToSearchThrough = @"-rangeOfString method finds and returns the range of the first occurrence of a given string within the receiver.";
BOOL contains = [stringToSearchThrough rangeOfString:@"occurence of a given string"].location != NSNotFound;
</code></pre>

blocks|key|3202998|text|如果不需要区分大小写字符串。试一试这个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3202999|NSString+*string++=+@"Hello+World!";

if([string+rangeOfString:@"hello"+options:NSCaseInsensitiveSearch].location+!=NSNotFound)
{
++++NSLog(@"found");
}
else
{
++++NSLog(@"not+found");
}|code-block|syntax|javascript|3203000|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If do not bother about case-sensitive string.
 Try this once.

<pre><code>NSString *string = @"Hello World!";

if([string rangeOfString:@"hello" options:NSCaseInsensitiveSearch].location !=NSNotFound)
{
 NSLog(@"found");
}
else
{
 NSLog(@"not found");
}
</code></pre>

blocks|key|416562|text|NSString+*categoryString+=+@"Holiday+Event";
if([categoryString+rangeOfString:@"Holiday"].location+==+NSNotFound)
{
++++//categoryString+does+not+contains+Holiday
}
else
{
++++//categoryString+contains+Holiday
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|416563|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>NSString *categoryString = @"Holiday Event";
if([categoryString rangeOfString:@"Holiday"].location == NSNotFound)
{
 //categoryString does not contains Holiday
}
else
{
 //categoryString contains Holiday
}
</code></pre>

blocks|key|3203028|text|请使用此代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3203029|NSString+*string+=+@"hello+bla+bla";
if+([string+rangeOfString:@"bla"].location+==+NSNotFound)+
{
++++NSLog(@"string+does+not+contain+bla");
}+
else+
{++
++++NSLog(@"string+contains+bla!");
}|code-block|syntax|javascript|3203030|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Please use this code

<pre class="lang-c prettyprint-override"><code>NSString *string = @"hello bla bla";
if ([string rangeOfString:@"bla"].location == NSNotFound) 
{
 NSLog(@"string does not contain bla");
} 
else 
{ 
 NSLog(@"string contains bla!");
}
</code></pre>

blocks|key|3203071|text|所以就我个人而言，我真的很讨厌NSNotFound，但我理解它的必要性。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3203072|但是有些人可能不了解与NSNotFound进行比较的复杂性。|3203073|例如，下面的代码：|3203074|-+(BOOL)doesString:(NSString*)string+containString:(NSString*)otherString+{
++++if([string+rangeOfString:otherString].location+!=+NSNotFound)
++++++++return+YES;
++++else
++++++++return+NO;
}|code-block|syntax|javascript|3203075|有它的问题：|3203076|1)很明显，如果otherString+=+nil，这段代码就会崩溃。一个简单的测试是：|3203077|NSLog(@"does+string+contain+string+-+%25@",+[self+doesString:@"hey"+containString:nil]+?+@"YES":+@"NO");|3203078|结果是!！撞车!！|3203079|2)对于刚接触objective-c的人来说，不太明显的是，当使用string+=+nil时，相同的代码不会崩溃。例如，下面的代码：|3203080|NSLog(@"does+string+contain+string+-+%25@",+[self+doesString:nil+containString:@"hey"]+?+@"YES":+@"NO");|3203081|这段代码是：|3203082|NSLog(@"does+string+contain+string+-+%25@",+[self+doesString:nil+containString:nil]+?+@"YES":+@"NO");|3203083|是否都会导致|3203084|does+string+contains+string+-+YES|3203085|这显然不是你想要的。|3203086|因此，我认为更好的解决方案是使用rangeOfString返回长度为0的事实，因此更好、更可靠的代码是：|3203087|-+(BOOL)doesString:(NSString*)string+containString:(NSString*)otherString+{
++++if(otherString+&&+[string+rangeOfString:otherString].length)
++++++++return+YES;
++++else
++++++++return+NO;
}|3203088|或者简单地说：|3203089|-+(BOOL)doesString:(NSString*)string+containString:(NSString*)otherString+{
++++return+(otherString+&&+[string+rangeOfString:otherString].length);
}|3203090|对于情况1和2，将返回|3203091|does+string+contains+string+-+NO|3203092|这是我的2美分;-)|3203093|请查看我的Gist获取更多有用的代码。|3203094|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/jlott1/038127cda6e23eaa0942^0|F|A|0|0|0|0|0|8|H|0|0|0|X|C|0|0|0|0|0|0|0|0|0|0|0|0|0|0|5|4|0|0^^$0|@$1|2|3|4|5|6|7|1Y|8|@$9|1Z|A|20|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|21|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|22|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|23|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|24|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|25|8|@$9|26|A|27|B|C]]|D|@]|E|$]]|$1|S|3|T|5|L|7|28|8|@]|D|@]|E|$M|N]]|$1|U|3|V|5|6|7|29|8|@]|D|@]|E|$]]|$1|W|3|X|5|6|7|2A|8|@$9|2B|A|2C|B|C]]|D|@]|E|$]]|$1|Y|3|Z|5|L|7|2D|8|@]|D|@]|E|$M|N]]|$1|10|3|11|5|6|7|2E|8|@]|D|@]|E|$]]|$1|12|3|13|5|L|7|2F|8|@]|D|@]|E|$M|N]]|$1|14|3|15|5|6|7|2G|8|@]|D|@]|E|$]]|$1|16|3|17|5|L|7|2H|8|@]|D|@]|E|$M|N]]|$1|18|3|19|5|6|7|2I|8|@]|D|@]|E|$]]|$1|1A|3|1B|5|6|7|2J|8|@]|D|@]|E|$]]|$1|1C|3|1D|5|L|7|2K|8|@]|D|@]|E|$M|N]]|$1|1E|3|1F|5|6|7|2L|8|@]|D|@]|E|$]]|$1|1G|3|1H|5|L|7|2M|8|@]|D|@]|E|$M|N]]|$1|1I|3|1J|5|6|7|2N|8|@]|D|@]|E|$]]|$1|1K|3|1L|5|L|7|2O|8|@]|D|@]|E|$M|N]]|$1|1M|3|1N|5|6|7|2P|8|@]|D|@]|E|$]]|$1|1O|3|1P|5|6|7|2Q|8|@]|D|@$9|2R|A|2S|1|2T]]|E|$]]|$1|1Q|3|-4|5|6|7|2U|8|@]|D|@]|E|$]]]|1R|$1S|$5|1T|1U|1V|E|$1W|1X]]]]

So personally I really hate <code>NSNotFound</code> but understand its necessity.

But some people may not understand the complexities of comparing against NSNotFound

For example, this code:

<pre><code>- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
 if([string rangeOfString:otherString].location != NSNotFound)
 return YES;
 else
 return NO;
}
</code></pre>

has its problems:

1) Obviously if <code>otherString = nil</code> this code will crash. a simple test would be:

<pre><code>NSLog(@"does string contain string - %@", [self doesString:@"hey" containString:nil] ? @"YES": @"NO");
</code></pre>

results in !! CRASH !!

2) What is not so obvious to someone new to objective-c is that the same code will NOT crash when <code>string = nil</code>. 
For example, this code:

<pre><code>NSLog(@"does string contain string - %@", [self doesString:nil containString:@"hey"] ? @"YES": @"NO");
</code></pre>

and this code:

<pre><code>NSLog(@"does string contain string - %@", [self doesString:nil containString:nil] ? @"YES": @"NO");
</code></pre>

will both result in

<pre><code>does string contains string - YES
</code></pre>

Which is clearly NOT what you want.

So the better solution that I believe works is to use the fact that rangeOfString returns the length of 0 so then a better more reliable code is this:

<pre><code>- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
 if(otherString &amp;&amp; [string rangeOfString:otherString].length)
 return YES;
 else
 return NO;
}
</code></pre>

OR SIMPLY:

<pre><code>- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
 return (otherString &amp;&amp; [string rangeOfString:otherString].length);
}
</code></pre>

which will for cases 1 and 2 will return

<pre><code>does string contains string - NO
</code></pre>

That's my 2 cents ;-)

Please check out my <a href="https://gist.github.com/jlott1/038127cda6e23eaa0942" rel="noreferrer">Gist</a> for more helpful code.

blocks|key|3203105|text|尝尝这个,|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3203106|NSString+*string+=+@"test+Data";
if+([[string+lowercaseString]+rangeOfString:@"data"].location+==+NSNotFound)+
{
++++NSLog(@"string+does+not+contain+Data");
}+++
else+
{
++++NSLog(@"string+contains+data!");
}|code-block|syntax|javascript|3203107|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

try this,

<pre class="lang-c prettyprint-override"><code>NSString *string = @"test Data";
if ([[string lowercaseString] rangeOfString:@"data"].location == NSNotFound) 
{
 NSLog(@"string does not contain Data");
} 
else 
{
 NSLog(@"string contains data!");
}
</code></pre>

blocks|key|1794736|text|在swift的情况下，可以使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1794737|let+string+=+"Package+#23"
if+string.containsString("Package+#")+{
++++//String+contains+substring
}
else+{
++++//String+does+not+contain+substring
}|code-block|syntax|javascript|1794738|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In case of swift, this can be used 

<pre><code>let string = "Package #23"
if string.containsString("Package #") {
 //String contains substring
}
else {
 //String does not contain substring
}
</code></pre>

blocks|key|1794784|text|最佳解决方案。就这么简单！如果您想查找一个单词或字符串的一部分。您可以使用此代码。在本例中，我们将检查word的值是否包含"acter“。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1794785|NSString+*word+=@"find+a+word+or+character+here";
if+([word+containsString:@"acter"]){
++++NSLog(@"It+contains+acter");
}+else+{
+++++NSLog+(@"It+does+not+contain+acter");
}|code-block|syntax|javascript|1794786|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Best solution. As simple as this! If you want to find a word or 
part of the string. You can use this code. In this example we are going to check if the value of word contains "acter".

<pre><code>NSString *word =@"find a word or character here";
if ([word containsString:@"acter"]){
 NSLog(@"It contains acter");
} else {
 NSLog (@"It does not contain acter");
}
</code></pre>

blocks|key|1161850|text|如果需要字符串的某个位置，则可以在Swift+3.0中使用此代码|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1161851|let+string+=+"This+is+my+string"
let+substring+=+"my"

let+position+=+string.range(of:+substring)?.lowerBound|code-block|syntax|javascript|1161852|entityMap^0|H|9|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

If certain position of the string is needed, this code comes to place in Swift 3.0:

<pre><code>let string = "This is my string"
let substring = "my"

let position = string.range(of: substring)?.lowerBound
</code></pre>

blocks|key|1794815|text|在Swift+4中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1794816|let+a+=+"Hello,+how+are+you?"
a.contains("Hello")+++//will+return+true|code-block|syntax|javascript|1794817|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In Swift 4:

<pre><code>let a = "Hello, how are you?"
a.contains("Hello") //will return true
</code></pre>

blocks|key|417123|text|第一个字符串包含或不包含第二个字符串，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|417124|NSString+*first+=+@"Banana";
NSString+*second+=+@"BananaMilk";
NSRange+range+=+[first+rangeOfString:second+options:NSCaseInsensitiveSearch];

if+(range.length+>+0)+{
++++NSLog(@"Detected");
}
else+{
++++NSLog(@"Not+detected");
}|code-block|syntax|javascript|417125|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

First string contain or not second string,

<pre><code>NSString *first = @"Banana";
NSString *second = @"BananaMilk";
NSRange range = [first rangeOfString:second options:NSCaseInsensitiveSearch];

if (range.length &gt; 0) {
 NSLog(@"Detected");
}
else {
 NSLog(@"Not detected");
}
</code></pre>

blocks|key|416703|text|将选项NSCaseInsensitiveSearch与rangeOfString:选项一起使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|416704|NSString+*me+=+@"toBe"+;
NSString+*target+=+@"abcdetobe"+;
NSRange+range+=+[target++rangeOfString:+me+options:+NSCaseInsensitiveSearch];
NSLog(@"found:+%25@",+(range.location+!=+NSNotFound)+?+@"Yes"+:+@"No");
if+(range.location+!=+NSNotFound)+{
//+your+code
}|code-block|syntax|javascript|416705|找到输出结果:是|416706|这些选项可以“或”在一起，包括：|416707|NSCaseInsensitiveSearch+NSLiteralSearch+NSBackwardsSearch及更多|416708|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Use the option NSCaseInsensitiveSearch with rangeOfString:options:

<pre><code>NSString *me = @"toBe" ;
NSString *target = @"abcdetobe" ;
NSRange range = [target rangeOfString: me options: NSCaseInsensitiveSearch];
NSLog(@"found: %@", (range.location != NSNotFound) ? @"Yes" : @"No");
if (range.location != NSNotFound) {
// your code
}
</code></pre>

Output result is found:Yes

The options can be "or'ed" together and include:

NSCaseInsensitiveSearch
NSLiteralSearch
NSBackwardsSearch and more

blocks|key|1164605|text|Swift+4及更高版本|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1164606|let+str+=+"Hello+iam+midhun"

if+str.contains("iam")+{
++//contains+substring
}
else+{
++//doesn't+contain+substring
}|code-block|syntax|javascript|1164607|Objective-C|1164608|NSString+*stringData+=+@"Hello+iam+midhun";

if+([stringData+containsString:@"iam"])+{
++++//contains+substring
}
else+{
++++//doesn't+contain+substring
}|1164609|entityMap^0|0|C|0|0|0|B|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|P|$]]

Swift 4 And Above

<pre><code>let str = "Hello iam midhun"

if str.contains("iam") {
 //contains substring
}
else {
 //doesn't contain substring
}
</code></pre>

Objective-C

<pre><code>NSString *stringData = @"Hello iam midhun";

if ([stringData containsString:@"iam"]) {
 //contains substring
}
else {
 //doesn't contain substring
}
</code></pre>

blocks|key|417156|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|417157|Swift+4.1、4.2:|offset|length|style|BOLD|417158|let+stringData+=+"Black+board"

//swift+quick+way+and+case+sensitive
if+stringData.contains("bla")+{
++++print("data+contains+string");
}

//case+sensitive
if+stringData.range(of:+"bla",options:+.caseInsensitive)+!=+nil+{
++++print("data+contains+string");
}else+{
++++print("data+does+not+contains+string");
}|code-block|syntax|javascript|417159|Objective-C的：|417160|NSString+*stringData+=+@"Black+board";

//Quick+way+and+case+sensitive
if+([stringData+containsString:@"bla"])+{
++++NSLog(@"data+contains+string");
}

//Case+Insensitive
if+([stringData+rangeOfString:@"bla"+options:NSCaseInsensitiveSearch].location+!=+NSNotFound)+{
+++NSLog(@"data+contains+string");
}else+{
+++NSLog(@"data+does+not+contain+string");
}|417161|entityMap^0|0|0|E|0|0|C|1|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|W|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|X|8|@$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|O|3|P|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

Try this: 

Swift 4.1 , 4.2:

<pre><code>let stringData = "Black board"

//swift quick way and case sensitive
if stringData.contains("bla") {
 print("data contains string");
}

//case sensitive
if stringData.range(of: "bla",options: .caseInsensitive) != nil {
 print("data contains string");
}else {
 print("data does not contains string");
}
</code></pre>

For Objective-C:

<pre><code>NSString *stringData = @"Black board";

//Quick way and case sensitive
if ([stringData containsString:@"bla"]) {
 NSLog(@"data contains string");
}

//Case Insensitive
if ([stringData rangeOfString:@"bla" options:NSCaseInsensitiveSearch].location != NSNotFound) {
 NSLog(@"data contains string");
}else {
 NSLog(@"data does not contain string");
}
</code></pre>

blocks|key|416724|text|-(Bool)checkIf:(String)parentString+containsSubstring:(String)checkString+{
++++NSRange+textRange+=[parentString+rangeOfString:checkString];
++++return+textRange.location+!=+NSNotFound+//+returns+true+if+parent+string+contains+substring+else+returns+false
++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|416725|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>-(Bool)checkIf:(String)parentString containsSubstring:(String)checkString {
 NSRange textRange =[parentString rangeOfString:checkString];
 return textRange.location != NSNotFound // returns true if parent string contains substring else returns false
 }
</code></pre>

How can I check if a string (<code>NSString</code>) contains another smaller string?

I was hoping for something like:

<pre><code>NSString *string = @"hello bla bla";
NSLog(@"%d",[string containsSubstring:@"hello"]);
</code></pre>

But the closest I could find was:

<pre><code>if ([string rangeOfString:@"hello"] == 0) {
 NSLog(@"sub string doesnt exist");
} 
else {
 NSLog(@"exists");
}
</code></pre>

Anyway, is that the best way to find if a string contains another string?

How do I check if a string contains another string in Objective-C?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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如何检查一个字符串(NSString)是否包含另一个更小的字符串？我希望是这样的：NSString *string = @"hello bla bla";NSLog(@"%d",[string containsSubstring:@"hello"]);但我能找到的最接近的是：if ([string rangeOfStr...

问如何在Objective-C中检查一个字符串是否包含另一个字符串？
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问如何在Objective-C中检查一个字符串是否包含另一个字符串？EN