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In Python how should I test if a variable is None, True or False
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a = 'foo' if a: print 'its true' a is not actually TRUE, it's just not none
– wesm
Apr 3 '15 at 21:06
...
pandas GroupBy columns with NaN (missing) values
...n the Missing Data section of the docs:
NA groups in GroupBy are automatically excluded. This behavior is consistent with R, for example.
One workaround is to use a placeholder before doing the groupby (e.g. -1):
In [11]: df.fillna(-1)
Out[11]:
a b
0 1 4
1 2 -1
2 3 6
In [12]: df.fil...
A Regex that will never be matched by anything
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This is actually quite simple, although it depends on the implementation / flags*:
$a
Will match a character a after the end of the string. Good luck.
WARNING:
This expression is expensive -- it will scan the entire line, find the en...
javac : command not found
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yes, i am sure. just look at the java-1.6.0-openjdk.x86_64 package information (scroll to the "Files" section) and see that there is no javac in that package. and then look at the OpenJDK Development Environment package.
– ax.
Mar 23 '11 at ...
how to create a file name with the current date & time in python?
... human readable.
from datetime import datetime
datetime.now().strftime("%Y_%m_%d-%I_%M_%S_%p")
'2020_08_12-03_29_22_AM'
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'UserControl' constructor with parameters in C#
Call me crazy, but I'm the type of guy that likes constructors with parameters (if needed), as opposed to a constructor with no parameters followed by setting properties. My thought process: if the properties are required to actually construct the object, they should go in the constructor. I get two...
Is gcc std::unordered_map implementation slow? If so - why?
...2531
get : 1565
So std::unordered_map in gcc-4.7 is broken (or my installation, which is an installation of gcc-4.7.0 on Ubuntu - and another installation which is gcc 4.7.1 on debian testing).
I will submit a bug report.. until then: DO NOT use std::unordered_map with gcc 4.7!
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Does Go have “if x in” construct similar to Python?
...ion without separate methods for every single type
– Allen
May 13 '15 at 4:33
29
It could be done...
How can I add or update a query string parameter?
... @JarónBarends - Tweak value check to check against undefined and null to allow setting 0 values
Third Update
There was a bug where removing a querystring variable directly before a hashtag would lose the hashtag symbol which has been fixed
Fourth Update
Thanks @rooby for pointing out a regex o...
Days between two dates? [duplicate]
...est for calendar checks.
from datetime import timedelta, datetime
def cal_days_diff(a,b):
A = a.replace(hour = 0, minute = 0, second = 0, microsecond = 0)
B = b.replace(hour = 0, minute = 0, second = 0, microsecond = 0)
return (A - B).days
if __name__ == '__main__':
x = datetime...