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Drop data frame columns by name
...op=FALSE to keep R from converting your data frame to a vector if you only select a single column. Don't forget that data frames are lists, so list selection (one-dimensional like I did) works perfectly well and always returns a list. Or a data frame in this case, which is why I prefer to use it.
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Code Wrap IntelliJ?
...o right click the gutter (the vertical bar where line number is shown) and select "Use Soft wraps" - thanks to Bajal for comment.
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Safe characters for friendly url [closed]
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To quote section 2.3 of RFC 3986:
"Characters that are allowed in a URI but do not have a reserved
purpose are called unreserved. These include uppercase and lowercase
letters, decimal digits, hyphen, period, underscore, and tilde."
ALPHA DIGIT "-" /...
Where is the C auto keyword used?
...because it declares that the car is broken down. The diagnostic is free of charge, but turning off the dashboard light will cost you eighty dollars. (Twenty or less, if you purchase your own USB dongle for on-board diagnostics from eBay).
The aforementioned extern auto my_car also requires a diagno...
SQL to determine minimum sequential days of access?
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The answer is obviously:
SELECT DISTINCT UserId
FROM UserHistory uh1
WHERE (
SELECT COUNT(*)
FROM UserHistory uh2
WHERE uh2.CreationDate
BETWEEN uh1.CreationDate AND DATEADD(d, @days, uh1.CreationDate)
) = @days O...
Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
... have to get rid of those first.
Here's a query that can find those IDs:
SELECT DISTINCT sourcecode_id FROM
sourcecodes_tags tags LEFT JOIN sourcecodes sc ON tags.sourcecode_id=sc.id
WHERE sc.id IS NULL;
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What is the correct way to restore a deleted file from SVN?
...go to TortoiseSVN -> Merge...
Make sure "Merge a range of revisions" is selected, click Next
In the "Revision range to merge" textbox, specify the revision that removed the file
Check the "Reverse merge" checkbox, click Next
Click Merge
That is completely untested, however.
Edited by OP: Thi...
Why does HTML think “chucknorris” is a color?
...om the blog post, we get the following:
Replace all nonvalid hexadecimal characters with 0's
chucknorris becomes c00c0000000
Pad out to the next total number of characters divisible by 3 (11 -> 12)
c00c 0000 0000
Split into three equal groups, with each component representing the correspond...
Hidden Features of Xcode
...m working with a large or unfamiliar project.
To show the Favorites Bar, select the following menu option:
View > Layout > Show Favorites Bar
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edited Apr 4 '11...
Hidden Features of Visual Studio (2005-2010)?
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Make a selection with ALT pressed - selects a square of text instead of whole lines.
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answered Sep 19 ...