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Is R's apply family more than syntactic sugar?
... makeSOCKcluster(c("localhost","localhost"))
parSapply(cl, 1:20, get("+"), 3)
This example uses a socket cluster, for which no additional software needs to be installed; otherwise you will need something like PVM or MPI (see Tierney's clustering page). snow has the following apply functions:
par...
How to get all subsets of a set? (powerset)
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137
The Python itertools page has exactly a powerset recipe for this:
from itertools import chain,...
How is “int* ptr = int()” value initialization not illegal?
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3
+1, the constant expression bit is important and missing from the top-2 upvoted answers.
– David Rodríguez - dribeas
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Define a lambda expression that raises an Exception
...7,'|\0\0\202\1\0',(),(),('x',),'','',1,''),{}
)(Exception())
And a python3 strong stomach solution:
type(lambda: 0)(type((lambda: 0).__code__)(
1,0,1,1,67,b'|\0\202\1\0',(),(),('x',),'','',1,b''),{}
)(Exception())
Thanks @WarrenSpencer for pointing out a very simple answer if you don't ca...
List comprehension vs map
...:
$ python -mtimeit -s'xs=range(10)' 'map(hex, xs)'
100000 loops, best of 3: 4.86 usec per loop
$ python -mtimeit -s'xs=range(10)' '[hex(x) for x in xs]'
100000 loops, best of 3: 5.58 usec per loop
An example of how performance comparison gets completely reversed when map needs a lambda:
$ pytho...
Moving matplotlib legend outside of the axis makes it cutoff by the figure box
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3 Answers
3
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How can I initialize a String array with length 0 in Java?
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232
As others have said,
new String[0]
will indeed create an empty array. However, there's one n...