escaping

问题 My original sql: INSERT INTO clients (name, phone) VALUES ('Vs'emandon', '333026660'); I read about E'' and tried this: INSERT INTO clients (name) VALUES ('VsE'''emandon); But this not working. http://www.sqlfiddle.com/#!15/f717e/2 回答1: Postgres follows the SQL standard. Quote from the manual: To include a single-quote character within a string constant, write two adjacent single quotes, e.g., 'Dianne''s horse' . Note that this is not the same as a double-quote character ( " ). INSERT INTO

问题 I am trying to check if a string is quoted by checking the first and last characters of the string. But my script fails when checking for the quote see output: AND was unexpected at this time. below. Code @echo off set mystring=Non quoted string set myquotedstring=^"My quoted string^" echo mystring: %mystring% echo myquotedstring: %myquotedstring% set result=%mystring:~0,1% echo first character of non quoted string is: %result% set result=%mystring:~-1% echo last character of non quoted

问题 I'm really confused about the escape character " \ " and its relation to the windows file system. In the following example: char* fwdslash = "c:/myfolder/myfile.txt"; char* backslash = "c:\myfolder\myfile.txt"; char* dblbackslash = "c:\\myfolder\\myfile.txt"; std::ifstream file(fwdslash); // Works std::ifstream file(dblbackslash); // Works std::ifstream file(backslash); // Doesn't work I get what you are doing here is escaping a special character so you can use it in this string. In no way by

问题 I am writing Ruby application for the back end service. There is a controller which would accept request from front-end. Here is the case, there is a GET request with a parameter containing character "\n". def register begin request = { id: params[:key] } ......... end end The "key" parameter is passing from AngularJs as "----BEGIN----- \n abcd \n ----END---- \n", but in the Ruby controller the parameter became "----BEGIN----- \\n abcd \\n ----END---- \\n" actually. Anyone has a good solution

问题 I am using C# to concatenate two strings with escapes sequences, that i want to skip so I'm using @ symbol before each string. It looks like this: string firstString = @"Use \n for line break. "; string secondString = @"Use \b for backspace"; return firstString + secondString; The question is: Will that escapes sequences be skipped in the returned value?; 回答1: Other answers are of course correct. For making it clear; This is covered in section 2.4.4.5 of the C# specification: 2.4.4.5 String

问题 I use C++ to process many files, and I have to write the file name in source code like this: "F:\\somepath\\subpath\\myfile" , I wonder that if there's any way to get rid of typing "\\" to get a character '\' in string literal context, i.e, I hope I can just write "F:\somepath\subpath\myfile" instead the boring one. 回答1: Solutions: use C++11 string literals: R"(F:\somepath\subpath\myfile)" Use boost::path with forward slashes: They will validate your path and raise exceptions for problems.

问题 I use C++ to process many files, and I have to write the file name in source code like this: "F:\\somepath\\subpath\\myfile" , I wonder that if there's any way to get rid of typing "\\" to get a character '\' in string literal context, i.e, I hope I can just write "F:\somepath\subpath\myfile" instead the boring one. 回答1: Solutions: use C++11 string literals: R"(F:\somepath\subpath\myfile)" Use boost::path with forward slashes: They will validate your path and raise exceptions for problems.

问题 I use C++ to process many files, and I have to write the file name in source code like this: "F:\\somepath\\subpath\\myfile" , I wonder that if there's any way to get rid of typing "\\" to get a character '\' in string literal context, i.e, I hope I can just write "F:\somepath\subpath\myfile" instead the boring one. 回答1: Solutions: use C++11 string literals: R"(F:\somepath\subpath\myfile)" Use boost::path with forward slashes: They will validate your path and raise exceptions for problems.

问题 In code I have developed some years ago I have been using this a lot to close the current form on pressing the Escape key at any moment: procedure TSomeForm.FormKeyPress(Sender: TObject; var Key: Char); begin if key = #27 then close; end; This behaviour is defined for the TForm. The form's KeyPreview property is be set to True to let the form react to key presses before any other components. It all works perfectly well for the best part of the program, however, when the Escape key is pressed

问题 In code I have developed some years ago I have been using this a lot to close the current form on pressing the Escape key at any moment: procedure TSomeForm.FormKeyPress(Sender: TObject; var Key: Char); begin if key = #27 then close; end; This behaviour is defined for the TForm. The form's KeyPreview property is be set to True to let the form react to key presses before any other components. It all works perfectly well for the best part of the program, however, when the Escape key is pressed