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尝试将 Ruby 代码移植到 ObjC 代码时遇到问题

红宝石：

clean_url = original_url.gsub(/\\u0026[^&]*/, "")

执行：

original_url = http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0&ms=au&expire=1368735912&id=e934f5f5c0743533&fexp=919374,909926,916713,916611,901474,924605,901208,929123,929915,929906,925714,929119,931202,928017,912518,911416,906906,904476,930807,919373,906836,933701,900345,926403,912711,929606,910075&sparams=cp,id,ip,ipbits,itag,ratebypass,source,upn,expire&sver=3&cp=U0hVTVdOU19GTENONV9PSFdKOnZFc0Uyc21YTVQw&ratebypass=yes&mv=m&source=youtube&itag=43&newshard=yes&mt=1368711866&ipbits=8&ip=92.114.198.83&key=yt1\u0026quality=medium\u0026type=video/webm&signature=AB8A6D618BDC38AF9D2E81916B863B724D2F12B6.8876CF4E106820B6443B4B06055BF90FD74B5794\u0026fallback_host=tc.v19.cache7.c.youtube.com,url=http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0

clean_url = http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0&ms=au&expire=1368735912&id=e934f5f5c0743533&fexp=919374,909926,916713,916611,901474,924605,901208,929123,929915,929906,925714,929119,931202,928017,912518,911416,906906,904476,930807,919373,906836,933701,900345,926403,912711,929606,910075&sparams=cp,id,ip,ipbits,itag,ratebypass,source,upn,expire&sver=3&cp=U0hVTVdOU19GTENONV9PSFdKOnZFc0Uyc21YTVQw&ratebypass=yes&mv=m&source=youtube&itag=43&newshard=yes&mt=1368711866&ipbits=8&ip=92.114.198.83&key=yt1&signature=AB8A6D618BDC38AF9D2E81916B863B724D2F12B6.8876CF4E106820B6443B4B06055BF90FD74B5794

Ruby 代码按预期工作。

对象代码：

NSError *error;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"\\u0026[^&]*" options:NSRegularExpressionCaseInsensitive error:&error];

NSString *originalUrl = @"http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0&ms=au&expire=1368735912&id=e934f5f5c0743533&fexp=919374,909926,916713,916611,901474,924605,901208,929123,929915,929906,925714,929119,931202,928017,912518,911416,906906,904476,930807,919373,906836,933701,900345,926403,912711,929606,910075&sparams=cp,id,ip,ipbits,itag,ratebypass,source,upn,expire&sver=3&cp=U0hVTVdOU19GTENONV9PSFdKOnZFc0Uyc21YTVQw&ratebypass=yes&mv=m&source=youtube&itag=43&newshard=yes&mt=1368711866&ipbits=8&ip=92.114.198.83&key=yt1\\u0026quality=medium\\u0026type=video/webm&signature=AB8A6D618BDC38AF9D2E81916B863B724D2F12B6.8876CF4E106820B6443B4B06055BF90FD74B5794\\u0026fallback_host=tc.v19.cache7.c.youtube.com,url=http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0";

NSString *cleanUrl = [regex stringByReplacingMatchesInString:originalUrl options:0 range:NSMakeRange(0, [originalUrl length]) withTemplate:@"bla"];

注意 withTemplate:@"bla" 因为没有它我们看不到问题出在哪里。

执行：

clean_url = http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0blablablablablablablablablablablablablablablablabla

提前致谢！

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1 回答 1

2

主要问题是您的正则表达式。它需要是：

@"\\\\u0026[^&]*"

您需要在正则表达式中使用两个反斜杠。在 C 和 Objective-C 中，反斜杠需要用另一个反斜杠转义。这意味着字符串需要 4 个反斜杠。

如果您只需要处理一个字符串，这是一种更简单的方法：

NSString *originalUrl = @"http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0&ms=au&expire=1368735912&id=e934f5f5c0743533&fexp=919374,909926,916713,916611,901474,924605,901208,929123,929915,929906,925714,929119,931202,928017,912518,911416,906906,904476,930807,919373,906836,933701,900345,926403,912711,929606,910075&sparams=cp,id,ip,ipbits,itag,ratebypass,source,upn,expire&sver=3&cp=U0hVTVdOU19GTENONV9PSFdKOnZFc0Uyc21YTVQw&ratebypass=yes&mv=m&source=youtube&itag=43&newshard=yes&mt=1368711866&ipbits=8&ip=92.114.198.83&key=yt1\\u0026quality=medium\\u0026type=video/webm&signature=AB8A6D618BDC38AF9D2E81916B863B724D2F12B6.8876CF4E106820B6443B4B06055BF90FD74B5794\\u0026fallback_host=tc.v19.cache7.c.youtube.com,url=http://r6---sn-hvaquxaxjvh-3p8l.c.youtube.com/videoplayback?upn=StTvWU7n7N0";
NSString *cleanURL = [originalURL stringByReplacingOccurrencesOfString:@"\\\\u0026[^&]*" withString:@"" options: NSRegularExpressionSearch range:NSMakeRange(0, originalURL.length)];

如果您需要使用正则表达式处理多个字符串，那么使用NSRegularExpression效率更高。

于 2013-05-16T15:39:55.653 回答