blocks|key|1110631|text|请参阅ICU+user+guide+on+regular+expressions。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1110632|如果你知道只有一个结果：|1110633|NSRegularExpression+*regex+=+[NSRegularExpression
++++regularExpressionWithPattern:@"\bworld\s%2B(.%2B)\s%2Bis\b"+options:0+error:NULL]

NSTextCheckingResult+*result+=+[regex+firstMatchInString:string
++++options:0+range:NSMakeRange(0,+[string+length]];

//+Gets+the+string+inside+the+first+set+of+parentheses+in+the+regex
NSString+*inside+=+[string+substringWithRange:[result+rangeAtIndex:1]];|code-block|syntax|javascript|1110634|B确保在world之前和is之后有一个单词边界(所以"hello+world+this+is‘t+a+string“不会匹配)。S会吞噬所有world之后和world之前的空格。.%2B？找到你要找的东西，用？让它不是贪婪的，所以"hello+world+this+is+a+string+hello+world+this+is+a+string“不会给你"this+a+string+hello+world+this”。|1110635|我将留给您来解决如何处理多个匹配的问题。NSRegularExpression文档应该会对您有所帮助。|1110636|如果你想确保匹配不会跨越句子边界，你可以这样做(%5E.%2B?)而不是(.%2B?)，或者您可以对字符串使用enumerateSubstringsInRange:options:usingBlock:并在选项中传递NSStringEnumerationBySentences。|1110637|这些东西都需要4.0%2B。如果你想支持3.0%2B，可以看看RegexKitLite。|1110638|entityMap|0|LINK|mutability|MUTABLE|url|http://userguide.icu-project.org/strings/regexp^0|3|11|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|6|7|14|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|15|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|C|$]]|$1|M|3|N|5|6|7|17|8|@]|9|@]|C|$]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|C|$]]|$1|Q|3|R|5|6|7|19|8|@]|9|@]|C|$]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]]|T|$U|$5|V|W|X|C|$Y|Z]]]]

See the <a href="http://userguide.icu-project.org/strings/regexp" rel="nofollow">ICU user guide on regular expressions</a>.

If you know there'll just be one result:

<pre><code>NSRegularExpression *regex = [NSRegularExpression
 regularExpressionWithPattern:@"\bworld\s+(.+)\s+is\b" options:0 error:NULL]

NSTextCheckingResult *result = [regex firstMatchInString:string
 options:0 range:NSMakeRange(0, [string length]];

// Gets the string inside the first set of parentheses in the regex
NSString *inside = [string substringWithRange:[result rangeAtIndex:1]];
</code></pre>

The \b makes sure there's a word boundary before world and after is (so "hello world this isn't a string" wouldn't match). The \s gobbles up any whitespace after world and before is. The .+? finds what you're looking for, with the ? making it non-greedy so that "hello world this is a string hello world this is a string" doesn't give you "this a string hello world this". 

I'll leave it up to you to figure out how to handle multiple matches. The NSRegularExpression documentation should help you out.

If you want to make sure the match doesn't cross sentence boundaries, you could do ([^.]+?) instead of (.+?), or you could use enumerateSubstringsInRange:options:usingBlock: on your string and pass NSStringEnumerationBySentences in the options.

This stuff all needs 4.0+. If you want to support 3.0+, look into RegexKitLite.

blocks|key|895915|text|如果它恰好是由空格分隔的字符串，您可以使用以下代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|895916|[string+componentsSeparatedByCharactersInSet:[NSCharacterSet+whitespaceCharacterSet]]|code-block|syntax|javascript|895917|或|895918|NSMutableArray+*parts+=+[NSMutableArray+arrayWithCapacity:1];

NSScanner+*scanner+=+[NSScanner+scannerWithString:string];
NSString+*token;
while+([scanner+scanUpToCharactersFromSet:[NSCharacterSet+whitespaceCharacterSet]]+intoString:&token])+{
++++[parts+addObject:token];
}|895919|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|$]]

If it happens to be just strings seperated by white spaces you can use the following code: Either 

<pre><code>[string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]
</code></pre>

OR

<pre><code>NSMutableArray *parts = [NSMutableArray arrayWithCapacity:1];

NSScanner *scanner = [NSScanner scannerWithString:string];
NSString *token;
while ([scanner scanUpToCharactersFromSet:[NSCharacterSet whitespaceCharacterSet]] intoString:&amp;token]) {
 [parts addObject:token];
}
</code></pre>

blocks|key|1110725|text|雅克给出的正则表达式解决方案是有效的，并且需要iOS+4.0和更高版本的警告是正确的。使用正则表达式也相当慢，如果搜索表达式是已知的字符串常量，则会造成过度杀伤力。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1110726|您可以使用NSString上的方法或名为NSScanner的类来解决这个问题，这两个类从MacOS2.0开始就已经可用，甚至早在iPhone+OSX10.0之前就已经可用了:)。|offset|length|style|CODE|1110727|那么，您想要的是NSString上的一个新方法，就像这样？|1110728|@interface+NSString+(CWAddition)
-+(NSString*)+stringBetweenString:(NSString*)start+andString:(NSString*)end;
@end|code-block|syntax|javascript|1110729|没问题，我们假设我们应该返回nil，因为找不到这样的字符串。|1110730|仅使用NSString的实现非常简单：|1110731|@implementation+NSString+(NSAddition)
-+(NSString*)+stringBetweenString:(NSString*)start+andString:(NSString*)end+{
++++NSRange+startRange+=+[self+rangeOfString:start];
++++if+(startRange.location+!=+NSNotFound)+{
++++++++NSRange+targetRange;
++++++++targetRange.location+=+startRange.location+%2B+startRange.length;
++++++++targetRange.length+=+[self+length]+-+targetRange.location;+++
++++++++NSRange+endRange+=+[self+rangeOfString:end+options:0+range:targetRange];
++++++++if+(endRange.location+!=+NSNotFound)+{
+++++++++++targetRange.length+=+endRange.location+-+targetRange.location;
+++++++++++return+[self+substringWithRange:targetRange];
++++++++}
++++}
++++return+nil;
}
@end|1110732|或者，您可以使用NSScanner类进行实现：|1110733|@implementation+NSString+(NSAddition)
-+(NSString*)+stringBetweenString:(NSString*)start+andString:(NSString*)end+{
++++NSScanner*+scanner+=+[NSScanner+scannerWithString:self];
++++[scanner+setCharactersToBeSkipped:nil];
++++[scanner+scanUpToString:start+intoString:NULL];
++++if+([scanner+scanString:start+intoString:NULL])+{
++++++++NSString*+result+=+nil;
++++++++if+([scanner+scanUpToString:end+intoString:&result])+{
++++++++++++return+result;
++++++++}
++++}
++++return+nil;
}
@end|1110734|entityMap^0|0|5|8|K|9|0|8|8|0|0|E|3|0|3|8|0|0|8|9|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@$D|12|E|13|F|G]|$D|14|E|15|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|16|8|@$D|17|E|18|F|G]]|9|@]|A|$]]|$1|J|3|K|5|L|7|19|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1A|8|@$D|1B|E|1C|F|G]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1D|8|@$D|1E|E|1F|F|G]]|9|@]|A|$]]|$1|S|3|T|5|L|7|1G|8|@]|9|@]|A|$M|N]]|$1|U|3|V|5|6|7|1H|8|@$D|1I|E|1J|F|G]]|9|@]|A|$]]|$1|W|3|X|5|L|7|1K|8|@]|9|@]|A|$M|N]]|$1|Y|3|-4|5|6|7|1L|8|@]|9|@]|A|$]]]|Z|$]]

The regular expressions solution that Jacques gives works, and the caveat of requiring iOS 4.0 and later is true. Using regular expressions is also quite slow, and an overkill if the search expressions are known string constants. 

You can solve the problem using methods on <code>NSString</code>, or a class named <code>NSScanner</code>, both have been available since iPhone OS 2.0 and long before that, since before Mac OS X 10.0 actually :).

So what you want is a new method on <code>NSString</code> like this?

<pre><code>@interface NSString (CWAddition)
- (NSString*) stringBetweenString:(NSString*)start andString:(NSString*)end;
@end
</code></pre>

No problem, and we assume we should return <code>nil</code> is no such strings could be found.

The implementation using <code>NSString</code> only is quite straight forward:

<pre><code>@implementation NSString (NSAddition)
- (NSString*) stringBetweenString:(NSString*)start andString:(NSString*)end {
 NSRange startRange = [self rangeOfString:start];
 if (startRange.location != NSNotFound) {
 NSRange targetRange;
 targetRange.location = startRange.location + startRange.length;
 targetRange.length = [self length] - targetRange.location; 
 NSRange endRange = [self rangeOfString:end options:0 range:targetRange];
 if (endRange.location != NSNotFound) {
 targetRange.length = endRange.location - targetRange.location;
 return [self substringWithRange:targetRange];
 }
 }
 return nil;
}
@end
</code></pre>

Or you could do the implementation using the <code>NSScanner</code> class:

<pre><code>@implementation NSString (NSAddition)
- (NSString*) stringBetweenString:(NSString*)start andString:(NSString*)end {
 NSScanner* scanner = [NSScanner scannerWithString:self];
 [scanner setCharactersToBeSkipped:nil];
 [scanner scanUpToString:start intoString:NULL];
 if ([scanner scanString:start intoString:NULL]) {
 NSString* result = nil;
 if ([scanner scanUpToString:end intoString:&amp;result]) {
 return result;
 }
 }
 return nil;
}
@end
</code></pre>

blocks|key|896011|text|只需对PeyloW的答案进行简单修改，即返回start和end字符串中的所有字符串：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|896012|-(NSMutableArray*)stringsBetweenString:(NSString*)start+andString:(NSString*)end
{

++NSMutableArray*+strings+=+[NSMutableArray+arrayWithCapacity:0];

++NSRange+startRange+=+[self+rangeOfString:start];

++for(+;;+)
++{

++++if+(startRange.location+!=+NSNotFound)
++++{

++++++NSRange+targetRange;

++++++targetRange.location+=+startRange.location+%2B+startRange.length;
++++++targetRange.length+=+[self+length]+-+targetRange.location;+++

++++++NSRange+endRange+=+[self+rangeOfString:end+options:0+range:targetRange];

++++++if+(endRange.location+!=+NSNotFound)
++++++{

++++++++targetRange.length+=+endRange.location+-+targetRange.location;
++++++++[strings+addObject:[self+substringWithRange:targetRange]];

++++++++NSRange+restOfString;

++++++++restOfString.location+=+endRange.location+%2B+endRange.length;
++++++++restOfString.length+=+[self+length]+-+restOfString.location;

++++++++startRange+=+[self+rangeOfString:start+options:0+range:restOfString];

++++++}
++++++else
++++++{
++++++++break;
++++++}

++++}
++++else
++++{
++++++break;
++++}

++}

++return+strings;

}|code-block|syntax|javascript|896013|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|$]]

Just a simple modification to PeyloW's answer, that returns all strings within the start and end strings:

<pre><code>-(NSMutableArray*)stringsBetweenString:(NSString*)start andString:(NSString*)end
{

 NSMutableArray* strings = [NSMutableArray arrayWithCapacity:0];

 NSRange startRange = [self rangeOfString:start];

 for( ;; )
 {

 if (startRange.location != NSNotFound)
 {

 NSRange targetRange;

 targetRange.location = startRange.location + startRange.length;
 targetRange.length = [self length] - targetRange.location; 

 NSRange endRange = [self rangeOfString:end options:0 range:targetRange];

 if (endRange.location != NSNotFound)
 {

 targetRange.length = endRange.location - targetRange.location;
 [strings addObject:[self substringWithRange:targetRange]];

 NSRange restOfString;

 restOfString.location = endRange.location + endRange.length;
 restOfString.length = [self length] - restOfString.location;

 startRange = [self rangeOfString:start options:0 range:restOfString];

 }
 else
 {
 break;
 }

 }
 else
 {
 break;
 }

 }

 return strings;

}
</code></pre>

I am trying to parse a string and get another string in the middle.

ie. 

Hello world this is a string

I need to find the string between "world" and "is" (this). I have looked around but haven't been able to figure it out yet, mainly because I am new to Objective C... Anyone have an idea of how to do this, with RegEx or without?

Get String Between Two Other Strings in ObjC

我正在尝试解析一个字符串，并在中间获取另一个字符串。即。Hello world这是一个字符串我需要找到"world“和"is”(this)之间的字符串。我已经环顾了四周，但还没有弄清楚，主要是因为我对Objective C还不熟悉。有没有人知道该怎么做，不管有没有RegEx？

问在ObjC中获取其他两个字符串之间的字符串
EN

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