緣起：

想獲取字符串中指定的字符，考慮用正則表達式，遂寫了如下的代碼：

[cpp] NSString *htmlStr = @"oauth_token=1a1de4ed4fca40599c5e5cfe0f4fba97&oauth_token_secret=3118a84ad910967990ba50f5649632fa&name=foolshit"; 
NSString *regexString = @"oauth_token=(\\w+)&oauth_token_secret=(\\w+)&name=(\\w+)"; 
NSString *matchedString1 = [htmlStr stringByMatching:regexString capture:1L]; 
NSString *matchedString2 = [htmlStr stringByMatching:regexString capture:2L]; 
NSString *matchedString3 = [htmlStr stringByMatching:regexString capture:3L]; 
NSString *htmlStr = @"oauth_token=1a1de4ed4fca40599c5e5cfe0f4fba97&oauth_token_secret=3118a84ad910967990ba50f5649632fa&name=foolshit";
NSString *regexString = @"oauth_token=(\\w+)&oauth_token_secret=(\\w+)&name=(\\w+)";
NSString *matchedString1 = [htmlStr stringByMatching:regexString capture:1L];
NSString *matchedString2 = [htmlStr stringByMatching:regexString capture:2L];
NSString *matchedString3 = [htmlStr stringByMatching:regexString capture:3L];獲取的結果如下：

1a1de4ed4fca40599c5e5cfe0f4fba97

3118a84ad910967990ba50f5649632fa

foolshit

思考：

雖然完成了任務，但是這麼寫顯然是低效的，因為每次獲取都需要啟用正則表達式。所以改進如下：

 

[cpp] NSArray *matchArray = NULL;    
matchArray = [htmlStr componentsMatchedByRegex:regexString]; 
NSLog(@"matchedString0 is %@", [matchArray objectAtIndex:0]); 
NSLog(@"matchedString1 is %@", [matchArray objectAtIndex:1]); 
NSLog(@"matchedString2 is %@", [matchArray objectAtIndex:2]); 
NSLog(@"matchedString3 is %@", [matchArray objectAtIndex:3]); 
NSArray *matchArray = NULL;  
matchArray = [htmlStr componentsMatchedByRegex:regexString];
NSLog(@"matchedString0 is %@", [matchArray objectAtIndex:0]);
NSLog(@"matchedString1 is %@", [matchArray objectAtIndex:1]);
NSLog(@"matchedString2 is %@", [matchArray objectAtIndex:2]);
NSLog(@"matchedString3 is %@", [matchArray objectAtIndex:3]);

獲取的結果如下：

oauth_token=1a1de4ed4fca40599c5e5cfe0f4fba97&oauth_token_secret=3118a84ad910967990ba50f5649632fa&name=foolshit

1a1de4ed4fca40599c5e5cfe0f4fba97

3118a84ad910967990ba50f5649632fa

foolshit

 

注：

我想通過 $1,$2⋯⋯，這種形式獲取，但是沒有成功。不知道哪位高手能實現。

 

摘自 zcl369369的專欄