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Convert data.frame column to a vector?
...ow because the df$x syntax returns a vector. I used this syntax for a long time, but when I had to start using df['name'] or df[n] to retrieve columns, I hit problems when I tried to send them to functions that expected vectors. Using df[[n]] or df[['x']] cleared things right up.
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Limitations of SQL Server Express
...e mode after a period of disuse.
Understanding SQL Express behavior: Idle time resource usage, AUTO_CLOSE and User Instances:
When SQL Express is idle it aggressively trims back the working memory set by writing the cached data back to disk and releasing the memory.
But this is easily worked ...
gdb split view with code
...@user146043, this seems the only way if you are running screen at the same time as ctrl-a is the way to initiate screen commands!
– olik79
May 29 '19 at 7:24
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Build a simple HTTP server in C [closed]
...red reader so that you can read requests one line (delimited by CRLF) at a time.
Read the very first line. Parse out the method, the request version and the path.
Implement header parsing for the "Header: value" syntax. Don't forget unfolding folded headers.
Check the request method, content type an...
Difference between a virtual function and a pure virtual function [duplicate]
...ions called through base class pointers/references will be resolved at run-time. That is, the dynamic type of the object is used instead of its static type:
Derived d;
Base& rb = d;
// if Base::f() is virtual and Derived overrides it, Derived::f() will be called
rb.f();
A pure virtual ...
Notepad++ add to every line
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Well, I am posting this after such a long time but this will the easiest of all.
To add text at the beginning/a-certain-place-from-start for all lines, just click there and do ALT+C and you will get the below box. Type in your text and click OK and it's done.
To ...
How to get the name of the calling method?
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caller[0][/`([^']*)'/, 1]
Will get included in backports when I get the time (or a pull request!).
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How to determine one year from now in Javascript
...e. You might think we'd be done there, but if we stopped it would return a timestamp, not a Date object so we wrap the whole thing in a Date constructor.
new Date(new Date().setFullYear(new Date().getFullYear() + 1))
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Initializing multiple variables to the same value in Java
...ple variables, and initialize multiple variables, but not both at the same time:
String one,two,three;
one = two = three = "";
However, this kind of thing (especially the multiple assignments) would be frowned upon by most Java developers, who would consider it the opposite of "visually simple"...
MySQL show status - active or total connections?
...---+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------------+--------+---------+------+-------+------------------+
| 3 | root | localhost | webapp | Query | 0 | NULL | show processlist |
| 5 | root | localh...