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How to drop columns by name in a data frame
... function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operator in column indexation :
R> df[ , -which(names(df) %in% c("z","u"))]
x y
1 1 2
2 2 3
3 3 4...
shared_ptr to an array : should it be used?
...or T[]. So you may write
shared_ptr<int[]> sp(new int[10]);
From n4659, [util.smartptr.shared.const]
template<class Y> explicit shared_ptr(Y* p);
Requires: Y shall be a complete type. The expression delete[] p, when T is an array type, or delete p, when T is not an array typ...
Script parameters in Bash
... ocrscript.sh
$1 # -from
$2 # /home/kristoffer/test.png
$3 # -to
$4 # /home/kristoffer/test.txt
It might be easier to omit the -from and the -to, like:
ocrscript.sh /home/kristoffer/test.png /home/kristoffer/test.txt
Then you'll have:
$1 # /home/kristoffer/test.png
$2 # /home...
Compute a confidence interval from sample data
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Do I need a content-type header for HTTP GET requests?
...ipient MAY either assume a media type of "application/octet-stream" ([RFC2046], Section 4.5.1) or examine the data to determine its type.
It means that the Content-Type HTTP header should be set only for PUT and POST requests.
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Can I change the root EBS device of my amazon EC2 instance?
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edited Apr 24 '17 at 18:52
cfstras
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answered Jun 16 '...
How do I reference an existing branch from an issue in GitHub?
...tHub:
References
Certain references are auto-linked:
SHA: be6a8cc1c1ecfe9489fb51e4869af15a13fc2cd2
User@SHA ref: mojombo@be6a8cc1c1ecfe9489fb51e4869af15a13fc2cd2
User/Project@SHA: mojombo/god@be6a8cc1c1ecfe9489fb51e4869af15a13fc2cd2
#Num: #1
User/#Num: mojombo#1
User/Project#Num: mojombo/god#1
I...
Automatically plot different colored lines
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edited Jun 22 '12 at 20:43
gnovice
122k1414 gold badges245245 silver badges350350 bronze badges
answer...
After array_filter(), how can I reset the keys to go in numerical order starting at 0
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