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Why were pandas merges in python faster than data.table merges in R in 2012?
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It looks like Wes may have discovered a known issue in data.table when the number of unique strings (levels) is large: 10,000.
Does Rprof() reveal most of the time spent in the call sortedmatch(levels(i[[lc]]), levels(x[[rc]])? This isn't really the join itself (t...
How do I show the value of a #define at compile-time?
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I know that this is a long time after the original query, but this may still be useful.
This can be done in GCC using the stringify operator "#", but it requires two stages.
#define XSTR(x) STR(x)
#define STR(x) #x
The value...
Parsing CSV files in C#, with header
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A CSV parser is now a part of .NET Framework.
Add a reference to Microsoft.VisualBasic.dll (works fine in C#, don't mind the name)
using (TextFieldParser parser = new TextFieldParser(@"c:\temp\test.csv"))
{
parser.TextFieldType = Field...
How do I grant myself admin access to a local SQL Server instance?
...the command prompt to stop the SQL Server service:
net stop mssqlserver
Now go to the directory where SQL server is installed. The directory can for instance be one of these:
C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\Binn
C:\Program Files\Microsoft SQL Server\MSSQL13.MS...
How to find all positions of the maximum value in a list?
... leading coefficients are ignored in big O
– michaelsnowden
Oct 23 '15 at 8:06
1
Theoretically O(...
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
...lin) and then set root password on phpMyAdmin . I forgot the password and now I am unable to login. When I try to change password through terminal I get:
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URLs: Dash vs. Underscore [closed]
...le Webmasters: youtube.com/watch?v=AQcSFsQyct8. Per that video (admittedly now 6 years old and possibly not representing the contemporary status quo), foo_bar is treated as a single word while foo-bar is treated as two words - precisely the opposite of what this answer speculates is the case.
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How to increase font size in the Xcode editor?
...font will be preselected in the font inspector. Whatever changes you make now
will be applied to the text types you selected in the 'Source Editor' window.
e.g. All Fonts > Menlo > Regular > 14
Close the windows you opened on this hunt for the holy grail.
Congratulations. Your may now...
When to use self over $this?
...I did get some more information that I found helpful further down, but for now I was just trying to figure out why I hit my class attributes with $this->attrib and the class constants with self::constant. This helped me understand that better
– MydKnight
Jul...
Why is there huge performance hit in 2048x2048 versus 2047x2047 array multiplication?
... evicted) than there is no problem with cache misses with matice2 either.
Now to go deeper in how caches works, if byte address of your variable is X, than the cache line for it would be (X >> 6) & (L - 1). Where L is total number of cache lines in your cache. L is always power of 2.
The...