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How do I get an empty array of any size in python?
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241
If by "array" you actually mean a Python list, you can use
a = [0] * 10
or
a = [None] * 10...
Determine the number of NA values in a column
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321
You're over-thinking the problem:
sum(is.na(df$col))
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How to convert int[] to Integer[] in Java?
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With Java 8, int[] can be converted to Integer[] easily:
int[] data = {1,2,3,4,5,6,7,8,9,10};
// To boxed array
Integer[] what = Arrays.stream( data ).boxed().toArray( Integer[]::new );
Integer[] ever = IntStream.of( data ).boxed().toArray( Integer[]::new );
// To boxed list
List<Integer> ...
Rails 3 migrations: Adding reference column?
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205
If you are using the Rails 4.x you can now generate migrations with references, like this:
ra...
Should commit messages be written in present or past tense? [closed]
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12 Answers
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Is there a printf converter to print in binary format?
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52 Answers
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How to run functions in parallel?
...ing'
for i in xrange(10000000): pass
print 'func1: finishing'
def func2():
print 'func2: starting'
for i in xrange(10000000): pass
print 'func2: finishing'
if __name__ == '__main__':
p1 = Process(target=func1)
p1.start()
p2 = Process(target=func2)
p2.start()
p1.join()
p2.join...
How does database indexing work? [closed]
...g on a field that isn’t sorted requires a Linear Search which requires N/2 block accesses (on average), where N is the number of blocks that the table spans. If that field is a non-key field (i.e. doesn’t contain unique entries) then the entire tablespace must be searched at N block accesses.
W...
How do I step out of a loop with Ruby Pry?
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edited May 22 '19 at 14:05
Qortex
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How to get a Docker container's IP address from the host
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52 Answers
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