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How to drop columns by name in a data frame
...he subset 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
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How to check if element exists using a lambda expression?
...urd
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answered Apr 11 '14 at 6:24
MasudulMasudul
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YouTube Video Embedded via iframe Ignoring z-index?
I'm trying to implement a horizontal multilevel dropdown navigation menu. Immediately below (vertically) the menu, I've got a YouTube video embedded via iframe. If I hover over one of the main level nav items in Firefox, the dropdown menu properly appears on top of the video.
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Fastest way to determine if an integer's square root is an integer
...ble.
if( bad255[y] )
return false;
// However, I just use a table of size 512
Finally, try to compute the square root using a method similar to Hensel's lemma. (I don't think it's applicable directly, but it works with some modifications.) Before doing that, I divide out all powers of 2 with...
Can I pass an array as arguments to a method with variable arguments in Java?
...nmp85
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How should I print types like off_t and size_t?
I'm trying to print types like off_t and size_t . What is the correct placeholder for printf() that is portable ?
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How do I get the MAX row with a GROUP BY in LINQ query?
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Way to read first few lines for pandas dataframe
...88504479 bytes, 5344499 lines):
In [1]: import pandas as pd
In [2]: time z = pd.read_csv("P00000001-ALL.csv", nrows=20)
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s
In [3]: len(z)
Out[3]: 20
In [4]: time z = pd.read_csv("P00000001-ALL.csv")
CPU times: user 27.63 s, sys: 1...
Is there a (repeat-last-command) in Emacs?
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answered Nov 9 '08 at 12:35
cmscms
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How can I delete the current line in Emacs?
...backspace # deletes previous 5 whole lines
Sometimes I also find C-x z helpful:
C-S-backspace # delete 1 whole line
C-x z # repeat last command
z # repeat last command again.
# Press z as many times as you wish.
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