[Regex] Why doesn't this pattern match?
Hello, can, please, somebody explain, why this code doesn't work? std::wstring str = L"Line \\n line \\n line \\n"; std::wstring result = L""; const boost::u32regex e = boost::make_u32regex(L"\\n"); std::wstring newText = L"\n"; result = boost::u32regex_replace(str, e, newText); After launching result == str... :((( I also tryed with const boost::u32regex e = boost::make_u32regex("\\n"); but result was the same... I am using Regex from bost 1.37.0 compilled with ICU 4.2.1 Visual Studio 2008.
can, please, somebody explain, why this code doesn't work?
std::wstring str = L"Line \\n line \\n line \\n"; std::wstring result = L""; const boost::u32regex e = boost::make_u32regex(L"\\n"); std::wstring newText = L"\n"; result = boost::u32regex_replace(str, e, newText);
After launching result == str... :(((
You're replacing each occurrence of \\n with \\n, so the string at the end should be exactly the same! :-) Unless I'm missing something yours, John.
John Maddock wrote:
can, please, somebody explain, why this code doesn't work?
std::wstring str = L"Line \\n line \\n line \\n"; std::wstring result = L""; const boost::u32regex e = boost::make_u32regex(L"\\n"); std::wstring newText = L"\n"; result = boost::u32regex_replace(str, e, newText);
You're replacing each occurrence of \\n with \\n, so the string at the end should be exactly the same! :-)
The replacement is "\n" not "\\n" so the '\' followed by 'n' in str should be replaced with a newline, right? _____ Rob Stewart robert.stewart@sig.com Software Engineer, Core Software using std::disclaimer; Susquehanna International Group, LLP http://www.sig.com IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.
The replacement is "\n" not "\\n" so the '\' followed by 'n' in str should be replaced with a newline, right?
No, a regular expression of \\n matches a single newline character - the first \ is swallowed by the compiler, then Boost.Regex gets to see the expression "\n" which it interprets as "match a newline". John.
participants (3)
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John Maddock -
Stewart, Robert -
Vitalij Gotovskij