如何在Objective-C中正确转义这个正则表达式？ [英] How can I escape this regex properly in Objective-C?

问题描述

我有以下正则表达式我想在Objective-C中转义

I have the following regex I would like to escape in Objective-C

/\B\$((?:[0-9]+(?=[a-z])|(?![0-9\.\:\_\-]))(?:[a-z0-9]|[\_\.\-\:](?![\.\_\.\-\:]))*[a-z0-9]+)/ig;

不完全确定如何转义它，所以它的工作原理Objective-C

Not exactly sure how to escape it so it works in Objective-C

更新：

NSString* pattern = @"/\\B\\$((?:[0-9]+(?=[a-z])|(?![0-9\\.\\:\\_\\-]))(?:[a-z0-9]|[\\_\\.\\-\\:](?![\\.\\_\\.\\-\\:]))*[a-z0-9]+)/ig;";
NSRegularExpression *usernameRegex = [[[NSRegularExpression alloc] initWithPattern:pattern
                                                                  options:NSRegularExpressionCaseInsensitive 
                                                                    error:nil];
                                                                        error:nil];

给我一​​个关于的错误Parse Issue - Unexpected Identifier

推荐答案

反斜杠在C字符串中用作转义字符。要将包含反斜杠的正则表达式作为正则表达式转义，您需要将它们加倍。

Backslashes are used as escape characters in C strings. To make a regexp that contains backslashes as regex escapes, you need to double them.

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