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Creating a singleton in Python
...mple implementation:
class Singleton(type):
_instances = {}
def __call__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
return cls._instances[cls]
class Logger(object):
__meta...
How to add /usr/local/bin in $PATH on Mac
...se it's on the right hand side of an assignment, but in general, and especially on Macs with their tradition of spacy pathnames, expansions like $PATH should be double-quoted as "$PATH".
share
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imp...
Remove duplicated rows using dplyr
... @hadley I like the unique() and distinct() function, however, they all remove the 2nd duplicate from the data frame. what if I want to have all 1st encounters of the duplicate value removed? How could this be done? Thanks for any help!
– FlyingDutch
Feb...
How to pass macro definition from “make” command line arguments (-D) to C source code?
I usually pass macro definitions from "make command line" to a "makefile" using the option :
-Dname=value. The definition is accessible inside the makefile.
...
Can I install Python 3.x and 2.x on the same Windows computer?
I'm running Windows and the shell/OS automatically runs Python based on the registry settings when you run a program on the command line. Will this break if I install a 2.x and 3.x version of Python on the same machine?
...
How do I script a “yes” response for installing programs?
...mazon Linux instances and I have a couple scripts to populate data and install all the programs I work with, but a couple of the programs ask:
...
Using git repository as a database backend
...d in my case. I'd like to emphasize that this rationale might not apply to all cases, so it's up to architect to decide.
Generally, the first main point my question misses is that I'm dealing with multi-user system that work in parallel, concurrently, using my server with a thin client (i.e. just a...
What's the meaning of Base SDK, iOS deployment target, Target, and Project in xcode
...ect can have multiple targets and you might not want the same settings for all targets. The project-level settings override the default settings and the target-level settings override the project-level settings.
For example I have projects with both OSX and iOS targets and some are ARC and some ar...
What is the common header format of Python files?
...
Its all metadata for the Foobar module.
The first one is the docstring of the module, that is already explained in Peter's answer.
How do I organize my modules (source files)? (Archive)
The first line of each file shoud be #!/us...
The Concept of 'Hold space' and 'Pattern space' in sed
... line. So what happens is this:
first line is read and inserted automatically into the pattern space
on the first line, first command is not executed; h copies the first line into the hold space.
now the second line replaces whatever was in the pattern space
on the second line, first we execute G,...