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Drop data frame columns by name
...a simple list of names :
DF <- data.frame(
x=1:10,
y=10:1,
z=rep(5,10),
a=11:20
)
drops <- c("x","z")
DF[ , !(names(DF) %in% drops)]
Or, alternatively, you can make a list of those to keep and refer to them by name :
keeps <- c("y", "a")
DF[keeps]
EDIT :
For those still not ac...
How do I read any request header in PHP
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15 Answers
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List of lists changes reflected across sublists unexpectedly
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593
When you write [x]*3 you get, essentially, the list [x, x, x]. That is, a list with 3 referenc...
How to safely upgrade an Amazon EC2 instance from t1.micro to large? [closed]
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5 Answers
5
Active
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Lock Escalation - What's happening here?
...e default in SQL 2008. Note that LOCK_ESCALATION isn't supported in SQL 2005, so you'll need to strip it if trying to run the script on a 2005 instance. Also, since TABLE is the default, you can safely remove that line when re-running your script.
Also note that, in SQL 2005 before this setting was...
Nginx serves .php files as downloads, instead of executing them
...y to run some .php file it's just downloading it...
for example... http://5.101.99.123/info.php it's working but... If I go to the main http://5.101.99.123 it's downloading my index.php :/
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Code Golf: Collatz Conjecture
...mand line:
;
; >> $ ./collatz 123
; >> 123 --> 370 --> 185 --> 556 --> 278 --> 139 --> 418 --> 209 --> 628 --> 314
; >> --> 157 --> 472 --> 236 --> 118 --> 59 --> 178 --> 89 --> 268 --> 134 --> 67
; >> --> 202 -->...
nodejs vs node on ubuntu 12.04
...rs have reported a few more solutions within the comments:
From @user229115
sudo update-alternatives --install /usr/bin/node node /usr/bin/nodejs 10
From AskUbuntu (user leftium)
sudo apt-get --purge remove node
sudo apt-get --purge remove nodejs
sudo apt-get install nodejs
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How can I remove the string “\n” from within a Ruby string?
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answered Nov 16 '10 at 2:53
ocodoocodo
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ERROR 1396 (HY000): Operation CREATE USER failed for 'jack'@'localhost'
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edited Nov 27 '19 at 1:54
Josh Correia
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answere...