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Changing every value in a hash in Ruby

... @Andrew Marshall Right you are, thanks. In Ruby 1.8, Hash.[] doesn't accept an array of array pairs, it requires an even number of direct arguments (hence the splat up front). – Phrogz Mar 4 '11 at 3...
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Extracting just Month and Year separately from Pandas Datetime column

... what actually does pd.Datetimeindex do? – JOHN Apr 16 '18 at 5:24 1 ...
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Finding current executable's path without /proc/self/exe

...e) method is to use argv[0]. Although it could be set to anything by the calling program, by convention it is set to either a path name of the executable or a name that was found using $PATH. Some shells, including bash and ksh, set the environment variable "_" to the full path of the executable be...
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How do I write the 'cd' command in a makefile?

... It is actually executing the command, changing the directory to some_directory, however, this is performed in a sub-process shell, and affects neither make nor the shell you're working from. If you're looking to perform more tasks wit...
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Is it a good practice to use an empty URL for a HTML form's action attribute? (action=“”)

...for compatibility with legacy content. [RFC3986] This definitely works in all current browsers, but may not work as expected in some older browsers ("browsers do weird things with an empty action="" attribute"), which is why the spec strongly discourages authors from leaving it empty: The action a...
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Unable to execute dex: Multiple dex files define Lcom/myapp/R$array;

...ing the Java Build Path and seeing this new item, and unchecking the originally-included support library solved the problem for me. – Tom Pace Sep 26 '13 at 17:20 9 ...
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How to add a 'or' condition in #ifdef

...¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|// #ifdef CONDITION_01 //| |// #define TEMP_MACRO //| |// #endif //| |// #ifdef CONDITION_02 //| |// #define TEMP_MACRO //| |// #endif ...
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Symfony 2: How do I check if a user is not logged in inside a template?

...any user is logged in. {% if app.user %} # user is logged in (any and all users, regardless of ROLE_*) {% elseif not app.user %} # user is not logged in (note the `not` in the `elseif` statement) {% endif %} Checking authentication status You can use the is_granted() method to check fo...
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How is the undo tree used in Vim?

... See also :h undo-redo, which lists all the commands and their usage. There are two ways to traverse the undo tree. One is to go "back in time". g+ and g- will traverse all of the nodes in the tree in chronological or reverse-chronological order (which can...
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What does character set and collation mean exactly?

...a symbol, the number 0 is the encoding for 'A', and the combination of all four letters and their encodings is a character set. Now, suppose that we want to compare two string values, 'A' and 'B'. The simplest way to do this is to look at the encodings: 0 for 'A' and 1 for 'B'. Be...