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Counting null and non-null values in a single query
... to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us;
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Numpy matrix to array
I am using numpy. I have a matrix with 1 column and N rows and I want to get an array from with N elements.
9 Answers
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How to define a function in ghci across multiple lines?
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For guards (like your example), you can just put them all on one line and it works (guards do ...
How to use shared memory with Linux in C
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166
There are two approaches: shmget and mmap. I'll talk about mmap, since it's more modern and fl...
PHP: How to send HTTP response code?
...TP response line and lets you replace that with a custom one
header("HTTP/1.1 200 OK");
However, this requires special treatment for (Fast)CGI PHP:
$sapi_type = php_sapi_name();
if (substr($sapi_type, 0, 3) == 'cgi')
header("Status: 404 Not Found");
else
header("HTTP/1.1 404 Not Found");...
snprintf and Visual Studio 2010
I'm unfortunate enough to be stuck using VS 2010 for a project, and noticed the following code still doesn't build using the non-standards compliant compiler:
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Can't pickle when using multiprocessing Pool.map()
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12 Answers
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EC2 Can't resize volume after increasing size
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14 Answers
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