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What does `:_*` (colon underscore star) do in Scala?
...to the method with repeated parameters (as denoted with Node* above).
The _* type annotation is covered in "4.6.2 Repeated Parameters" of the SLS.
The last value parameter of a parameter section may be suffixed by “*”, e.g. (..., x:T *). The type of such a repeated parameter inside th...
What are metaclasses in Python?
... the 'class' statement) by calling the metaclass. Combined with the normal __init__ and __new__ methods, metaclasses therefore allow you to do 'extra things' when creating a class, like registering the new class with some registry or replace the class with something else entirely.
When the class st...
List goals/targets in GNU make that contain variables in their definition
...ion would be to create a trivial makefile, dummy.mk, with these contents:
__all_targets__: ; #no-op
Now invoke make as make -p -f Makefile -f dummy.mk __all_targets__. On any substantial build, the difference in the amount of output generated by make is significant. For example:
$ gmake -pn | ...
Iterating through a JSON object
...
Your loading of the JSON data is a little fragile. Instead of:
json_raw= raw.readlines()
json_object = json.loads(json_raw[0])
you should really just do:
json_object = json.load(raw)
You shouldn't think of what you get as a "JSON object". What you have is a list. The list contains two d...
Multiprocessing: How to use Pool.map on a function defined in a class?
...
[p.join() for p in proc]
return [p.recv() for (p, c) in pipe]
if __name__ == '__main__':
print parmap(lambda x: x**x, range(1, 5))
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Difference between left join and right join in SQL Server [duplicate]
... two table with following records:
Table A
id firstname lastname
___________________________
1 Ram Thapa
2 sam Koirala
3 abc xyz
6 sruthy abc
Table B
id2 place
_____________
1 Nepal
2 USA
3 Lumbini
5 Kathmandu
Inne...
Access nested dictionary items via a list of keys?
..., 'z': 3}, 'w': 3}}
Note that the Python PEP8 style guide prescribes snake_case names for functions. The above works equally well for lists or a mix of dictionaries and lists, so the names should really be get_by_path() and set_by_path():
from functools import reduce # forward compatibility for Py...
Split a string by a delimiter in python
How to split this string where __ is the delimiter
3 Answers
3
...
Nested classes' scope?
...
class Outer(object):
outer_var = 1
class Inner(object):
@property
def inner_var(self):
return Outer.outer_var
This isn't quite the same as similar things work in other languages, and uses global lookup instead of sco...
C++ compiling on Windows and Linux: ifdef switch [duplicate]
...
use:
#ifdef __linux__
//linux code goes here
#elif _WIN32
// windows code goes here
#else
#endif
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