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Is it possible to set a number to NaN or infinity?
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On python >= 2.6, you can just use math.isnan() and math.isinf()
– Agos
May 9 '11 at 10:21
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How can I return pivot table output in MySQL?
...w.artfulsoftware.com/infotree/qrytip.php?id=78
I advise reading this post and adapt this solution to your needs.
Update
After the link above is currently not available any longer I feel obliged to provide some additional information for all of you searching for mysql pivot answers in here. It rea...
Is short-circuiting logical operators mandated? And evaluation order?
Does the ANSI standard mandate the logical operators to be short-circuited, in either C or C++?
7 Answers
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IF… OR IF… in a windows batch file
...lternative is to use an indicator variable. Initialize it to be undefined, and then define it only if any one of the OR conditions is true. Then use IF DEFINED as a final test - no need to use delayed expansion.
FOR ..... DO (
set "TRUE="
IF cond1 set TRUE=1
IF cond2 set TRUE=1
IF defined TR...
Database sharding vs partitioning
...two words that keep on showing up with regards to databases are sharding and partitioning . I looked up descriptions but still ended up confused.
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How to check iOS version?
...lable(iOS 9, *) {}
In Objective-C, you need to check the system version and perform a comparison.
[[NSProcessInfo processInfo] operatingSystemVersion] in iOS 8 and above.
As of Xcode 9:
if (@available(iOS 9, *)) {}
The full answer …
In Objective-C, and Swift in rare cases, it's better to...
Why is XOR the default way to combine hashes?
Say you have two hashes H(A) and H(B) and you want to combine them. I've read that a good way to combine two hashes is to XOR them, e.g. XOR( H(A), H(B) ) .
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MySQL error: key specification without a key length
...r BLOB types such as TINYBLOB, MEDIUMBLOB, LONGBLOB, TINYTEXT, MEDIUMTEXT, and LONGTEXT that you try to make a primary key or index. With full BLOB or TEXT without the length value, MySQL is unable to guarantee the uniqueness of the column as it’s of variable and dynamic size. So, when using BLOB ...
Cookies on localhost with explicit domain
...sic thing about cookies. On localhost, when I set a cookie on server side and specify the domain explicitly as localhost (or .localhost). the cookie does not seem to be accepted by some browsers.
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Accessing class variables from a list comprehension in the class definition
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Class scope and list, set or dictionary comprehensions, as well as generator expressions do not mix.
The why; or, the official word on this
In Python 3, list comprehensions were given a proper scope (local namespace) of their own, to p...