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How do you delete a column by name in data.table?
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Any of the following will remove column foo from the data.table df3:
# Method 1 (and preferred as it takes 0.00s even on a 20GB data.table)
df3[,foo:=NULL]
df3[, c("foo","bar"):=NULL] # remove two columns
myVar = "foo"
df3[, (myVar):=NULL] # lookup myVar contents...
How to load/edit/run/save text files (.py) into an IPython notebook cell?
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EDIT: Starting from IPython 3 (now Jupyter project), the notebook has a text editor that can be used as a more convenient alternative to
load/edit/save text files.
A text file can be loaded in a notebook cell with the magic command %loa...
How to reference generic classes and methods in xml documentation
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Thanks for that answer! It's actually missing from MSDN's page on <see>: msdn.microsoft.com/en-us/library/acd0tfbe.aspx
– joce
Apr 16 '11 at 20:56
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Python assigning multiple variables to same value? list behavior
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If you're coming to Python from a language in the C/Java/etc. family, it may help you to stop thinking about a as a "variable", and start thinking of it as a "name".
a, b, and c aren't different variables with equal values; they're different names for...
Beyond Stack Sampling: C++ Profilers
...ng data. To get good output I need configure it to load the debug symbols from my 3rd party and system libraries. Be sure to do the same, otherwise you'll see that CRT is taking 20% of your application's time when what's really going on is malloc is trashing the heap and eating up 15%.
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How to properly seed random number generator
...next random integer.
Move the rand.Seed(time.Now().UTC().UnixNano()) line from the randInt function to the start of the main and everything will be faster.
Note also that I think you can simplify your string building:
package main
import (
"fmt"
"math/rand"
"time"
)
func main() {
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How to find encoding of a file via script on Linux?
...ere are no non-ascii chars in your utf-8 file, then it's indistinguishable from ascii :)
– vadipp
Mar 2 '17 at 10:36
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show 10 more comments...
ggplot with 2 y axes on each side and different scales
...e plotting package I'm using doesn't support that." So I'm switching away from ggplot today for this particular project. =(
– Ken Williams
May 31 '12 at 22:14
63
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How can I remove all text after a character in bash?
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cut can read from stdin, so it is better especially when you have a very long string that you need to process, like the contents of a file.
– Sahas
Apr 26 '17 at 8:34
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Why does @foo.setter in Python not work for me?
...ly you need to use new-style classes instead (in python 2 you must inherit from object). Just declare your class as MyClass(object):
class testDec(object):
@property
def x(self):
print 'called getter'
return self._x
@x.setter
def x(self, value):
print 'ca...