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What's the fastest way to merge/join data.frames in R?
..., in fact, they are placed on tables which were overwritten before the sql select ever runs and that, in part, accounts for why its so slow. The idea of sqldf is that the data frames in your R session constitute the data base, not the tables in sqlite. Thus each time the code refers to an unqualif...
LEFT JOIN vs. LEFT OUTER JOIN in SQL Server
...default is INNER if you just specify JOIN. In other words, this is legal:
SELECT *
FROM A JOIN B ON A.X = B.Y
Here's a list of equivalent syntaxes:
A LEFT JOIN B A LEFT OUTER JOIN B
A RIGHT JOIN B A RIGHT OUTER JOIN B
A FULL JOIN B A FULL OUTER JOIN B
A INNER JOIN...
How to prevent ifelse() from turning Date objects into numeric objects
...documented option to have base::ifelse() preserve attributes based on user selection of which attributes to preserve. The request is here: https://bugs.r-project.org/bugzilla/show_bug.cgi?id=16609 - It has already been flagged as "WONTFIX" on the grounds that it has always been the way it is now, b...
Input with display:block is not a block, why not?
...up with all sorts of retarded hacks like using 99% width to get inputs and selects to match. I really want a way to treat an input like a div and I was hoping I'd just overlooked something.
– SpliFF
Jun 23 '09 at 6:05
...
How can I determine what font a browser is actually using to render some text?
...that, but Safari needs you to copy some text and investigate that.
First, select some text. In Firefox, the Page Inspector has a Fonts view:
This will also tell you if fonts were downloaded, and which style is used, such as Regular, ExtraLight, Italic, BoldItalic and all.
For Chrome, go into De...
Static hosting on Amazon S3 - DNS Configuration
...site. With the AWS console ( https://console.aws.amazon.com/s3/ ) you can select your bucket, click properties, then select the "Website" tab. Click enabled and set your index document to "index.html" and your error document to "404.html". You will also need to set your bucket with access permissi...
Best way to check if a Data Table has a null value in it
... || dr1["Columnname"].ToString() == ""
select Columnname);
Here Replace Columnname with table column name and "" your search item in above code we looking null value.
share
|
...
How can I sort arrays and data in PHP?
... $array[$j] = $tem;
}
}
}
return $array;
}
Selection sort
From the Wikipedia article on Selection sort:
In computer science, selection sort is a sorting algorithm, specifically an in-place comparison sort. It has O(n2) time complexity, making it inefficient on la...
Multiple INSERT statements vs. single INSERT with multiple VALUES
...t
One place where this information is leveraged is shown by @Lieven here
SELECT *
FROM (VALUES ('Lieven1', 1),
('Lieven2', 2),
('Lieven3', 3))Test (name, ID)
ORDER BY name, 1/ (ID - ID)
Because at compile time it can determine that the Name column has no duplicates it...
How to improve Netbeans performance?
...ions in netbeans.conf :
# Note that default -Xmx and -XX:MaxPermSize are selected for you automatically.
# You can find these values in var/log/messages.log file in your userdir.
# The automatically selected value can be overridden by specifying -J-Xmx or
# -J-XX:MaxPermSize= here or on the comman...