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PostgreSQL Crosstab Query
... | 4 | 5
C | 7 | -- !!
No need for casting and renaming.
Note the incorrect result for C: the value 7 is filled in for the first column. Sometimes, this behavior is desirable, but not for this use case.
The simple form is also limited to exactly three columns ...
Why do I get a segmentation fault when writing to a “char *s” initialized with a string literal, but
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Whenever using "%p" on printf, you should cast the pointer to void * as in printf("%p", (void *)str); When printing a size_t with printf, you should use "%zu" if using the latest C standard (C99).
– Chris Young
Oct 3 '08 at 7:44...
What's the difference(s) between .ToList(), .AsEnumerable(), AsQueryable()?
...st() along the way.
What do these methods do?
AsEnumerable and AsQueryable cast or convert to IEnumerable or IQueryable, respectively. I say cast or convert with a reason:
When the source object already implements the target interface, the source object itself is returned but cast to the target int...
Is it possible to capture a Ctrl+C signal and run a cleanup function, in a “defer” fashion?
I want to capture the Ctrl+C ( SIGINT ) signal sent from the console and print out some partial run totals.
10 Answers
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Does the Java &= operator apply & or &&?
...So a &= b; is equivalent to a = a & b;.
(In some usages, the type-casting makes a difference to the result, but in this one b has to be boolean and the type-cast does nothing.)
And, for the record, a &&= b; is not valid Java. There is no &&= operator.
In practice, there...
Python: Get relative path from comparing two absolute paths
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os.path.commonprefix() and os.path.relpath() are your friends:
>>> print os.path.commonprefix(['/usr/var/log', '/usr/var/security'])
'/usr/var'
>>> print os.path.commonprefix(['/tmp', '/usr/var']) # No common prefix: the root is...
Redirect stdout to a file in Python?
... common method is to use shell redirection when executing (same on Windows and Linux):
$ python foo.py > file
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How to find if directory exists in Python
...en classes are callable. Also, functions are first-class values in Python, and you can use them without the parentheses notation, like in existing = filter(os.path.isdir(['/lib', '/usr/lib', '/usr/local/lib'])
– phihag
Mar 30 '13 at 7:38
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Python: What OS am I running on?
...wered Aug 5 '08 at 3:27
Louis BrandyLouis Brandy
15.1k33 gold badges3333 silver badges2929 bronze badges
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How do I check if a SQL Server text column is empty?
...he added overhead of calling SQL Functions like DataLength(), IsNull(), or Cast(). Maybe the generated query plan is the same (I didn't check); still I find this to be a far cleaner approach.
– MikeTeeVee
Nov 13 '19 at 11:49
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