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pandas GroupBy columns with NaN (missing) values
...n the Missing Data section of the docs:
NA groups in GroupBy are automatically excluded. This behavior is consistent with R, for example.
One workaround is to use a placeholder before doing the groupby (e.g. -1):
In [11]: df.fillna(-1)
Out[11]:
a b
0 1 4
1 2 -1
2 3 6
In [12]: df.fil...
MySQL Removing Some Foreign keys
...You can use this to find foreign key constraints: SELECT * FROM information_schema.table_constraints WHERE constraint_schema = '<your db name>' AND constraint_type = 'FOREIGN KEY'
– Gayan Dasanayake
Aug 26 '17 at 2:48
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In Python, what is the difference between “.append()” and “+= []”?
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In general case append will add one item to the list, while += will copy all elements of right-hand-side list into the left-hand-side list.
Update: perf analysis
Comparing bytecodes we can assume that append version wastes cycles in LOAD_ATTR + CALL_FUNCTION, and += version -- in BUILD_LIST. App...
Stateless vs Stateful - I could use some concrete information
...programming. I'm interested because I want to learn more about it, but I really can't find any good articles about it. I've read dozens of articles on the web which vaguely discuss the subject, or they're talking about web servers and sessions - which are also 'bout stateful vs stateless, but I'm in...
How do I verify a method was called exactly once with Moq?
How do I verify a method was called exactly once with Moq? The Verify() vs. Verifable() thing is really confusing.
3 A...
Could not find default endpoint element
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"This error can arise if you are calling the service in a class library and calling the class library from another project."
In this case you will need to include the WS configuration settings into the main projects app.config if its a winapp or web.config i...
How to get NSDate day, month and year in integer format?
...2017
Swift 3.0 (It's an iteration of previous answers, but solves it for all your future app projects)
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How to connect android emulator to the internet
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Check your firewall settings - as @moon_walker333 mentions in this thread. AVG was blocking my application.
– ccbunney
Apr 20 '13 at 8:06
1
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How to write a test which expects an Error to be thrown in Jasmine?
... not possible"));
you should be passing a function into the expect(...) call. Your incorrect code:
// incorrect:
expect(parser.parse(raw)).toThrow(new Error("Parsing is not possible"));
is trying to actually call parser.parse(raw) in an attempt to pass the result into expect(...),
...
Why doesn't GCC optimize a*a*a*a*a*a to (a*a*a)*(a*a*a)?
...scientific application. One thing I noticed is that GCC will optimize the call pow(a,2) by compiling it into a*a , but the call pow(a,6) is not optimized and will actually call the library function pow , which greatly slows down the performance. (In contrast, Intel C++ Compiler , executable ...