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Counting null and non-null values in a single query
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This works for Oracle and SQL Server (you might be able 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) fro...
In a .csproj file, what is for?
... differences.
None - The file is not included in the project output group and is not compiled in the build process. An example is a text file that contains documentation, such as a Readme file.
Content - The file is not compiled, but is included in the Content output group. For example, this settin...
Programmatically selecting text in an input field on iOS devices (mobile Safari)
...ur playing with various solutions. Calling setSelectionRange() in a focus handler works when you trigger .focus() programmatically, but when you manually tap into the text input on iOS, the selection does not happen. Suffice it to say, all you need to do is call setSelectionRange() within a setTimeo...
What is the difference between save and insert in Mongo DB?
What is the difference between save and insert in Mongo DB?
both looks the same
9 Answers
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How to know if other threads have finished?
...ted, or
Unorthodox, for each Thread in question, call setUncaughtExceptionHandler to call a method in your object, and program each Thread to throw an uncaught Exception when it completes, or
Use locks or synchronizers or mechanisms from java.util.concurrent, or
More orthodox, create a listener in y...
How do I create a crontab through a script
...a text file with the job configured, then copy it to the cron spool folder and make sure it has the right permissions (600).
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What are these attributes: `aria-labelledby` and `aria-hidden`
...sible Rich Internet Applications (ARIA) defines ways to make Web
content and Web applications (especially those developed with Ajax and
JavaScript) more accessible to people with disabilities.
To be precise for your question, here is what your attributes are called as ARIA attribute states and...
IsNothing versus Is Nothing
Does anyone here use VB.NET and have a strong preference for or against using IsNothing as opposed to Is Nothing (for example, If IsNothing(anObject) or If anObject Is Nothing... )? If so, why?
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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 not care about spacing)
let abs n | n >= 0 = n | otherwise = -n
If you wanted to write your function with multiple definitions that pattern match on the arguments, like this:
fact 0 = 1
fact n =...
How to make a flat list out of list of lists?
...for item in sublist]
As evidence, you can use the timeit module in the standard library:
$ python -mtimeit -s'l=[[1,2,3],[4,5,6], [7], [8,9]]*99' '[item for sublist in l for item in sublist]'
10000 loops, best of 3: 143 usec per loop
$ python -mtimeit -s'l=[[1,2,3],[4,5,6], [7], [8,9]]*99' 'sum(l...