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How to drop columns by name in a data frame
...ubset 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
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Does free(ptr) where ptr is NULL corrupt memory?
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227
7.20.3.2 The free function
Synopsis
#include <stdlib.h>
void free(void *ptr); ...
How to check if a string contains an element from a list in Python
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– Lauritz V. Thaulow
May 31 '14 at 23:47
5
And if I want to know what ext is when any() returns True...
Why am I merging “remote-tracking branch 'origin/develop' into develop”?
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edited May 23 '17 at 12:34
Community♦
111 silver badge
answered Jun 20 '11 at 4:55
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Difference of keywords 'typename' and 'class' in templates?
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447
typename and class are interchangeable in the basic case of specifying a template:
template<...
Update Item to Revision vs Revert to Revision
...copy which were made after the selected revision (in your example rev. 96,97,98,99,100)
Your working copy is now in modified state.
The file content of both scenarions is same, however in first case you have an unmodified working copy and you cannot commit your changes(as your workingcopy is not p...
Add legend to ggplot2 line plot
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answered Apr 27 '12 at 10:57
csgillespiecsgillespie
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When to make a type non-movable in C++11?
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17
+1 a less exotic example of something that can't be moved because it has a special address is a node in a directed graph structure.
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Is it safe to ignore the possibility of SHA collisions in practice?
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Arslan Ali
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answered Oct 25 '10 at 12:14
Thomas PorninThomas...
Force LF eol in git repo and working copy
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237
Without a bit of information about what files are in your repository (pure source code, images, ...