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Split (explode) pandas dataframe string entry to separate rows
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GroupBy.apply should work (I just tried it against master). However, in this case you don't really need to go through the extra step of grouping since you're generating the data by row right?
– Chang She...
Curious null-coalescing operator custom implicit conversion behaviour
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If you take a look at the generated code for the Left-grouped case it actually does something like this (csc /optimize-):
C? first;
A? atemp = a;
B? btemp = (atemp.HasValue ? new B?(a.Value) : b);
if (btemp.HasValue)
{
first = new C?((atemp.HasValue ? new B?(a.Value) : b).V...
What framework for MVVM should I use? [closed]
...e MVVM framework, and I've had input into others through the WPF Disciples group, so I'm a little bit biased. Saying that, here goes:
Microsofts MVVM Toolkit - this is still very much in the alpha stages. When it was originally released, it took a bit of a savaging from the Disciples because of wha...
Validate that a string is a positive integer
...o)
(?:...|...): Allow one of these two options (without creating a capture group):
(0|...): Allow 0 on its own...
(...|[1-9]\d*): ...or a number starting with something other than 0 and followed by any number of decimal digits.
$: Match end of string.
If you want to disallow 0 (because it's not...
ICollection Vs List in Entity Framework
... Normal Linq operations do not add or mutate things, they simply filter, group, project, etc. Forward-only, read-only sequences are all that's necessary to support those operations. When you have a Linq provider such as Entity Framework that deals with data persistence, the ability to Add is a sub...
How to make the 'cut' command treat same sequental delimiters as one?
... field: 1
4th field: 2
4th field: 3
4th field: 4
sed
This catches three groups of spaces and no spaces with ([^ ]*[ ]*){3}. Then, it catches whatever coming until a space as the 4th field, that it is finally printed with \1.
$ sed -r 's/^([^ ]*[ ]*){3}([^ ]*).*/\2/' a
1
2
3
4
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Why is creating a new process more expensive on Windows than Linux?
...ility database. This step causes enough overhead that Microsoft provides a group policy option to disable the compatibility engine on WS2003 for performance reasons.
The Win32 runtime libraries (kernel32.dll, etc.) also do a lot of registry reads and initialization on startup that don't apply to UN...
Proper MIME type for OTF fonts
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Since Feb 2017 RFC 8081 groups all MIME types for fonts under the top level font media type. The older MIME types from my original posting are now listed as deprecated.
Font types as listed by IANA are now:
.otf -> font/otf
.sfnt -> font...
Storing DateTime (UTC) vs. storing DateTimeOffset
...o most common requirements - local time for local reports and UTC time for group reports.
The local time is stored in the DATETIME portion of the DATETIMEOFFSET and the OFFSET from UTC is stored in the OFFSET portion, thus conversion is simple and, since it requires no knowledge of the timezone the...
Why malloc+memset is slower than calloc?
...y there to take small allocations (anything from 1 byte to 100s of KB) and group them into larger pools of memory. For example, if you allocate 16 bytes, malloc() will first try to get 16 bytes out of one of its pools, and then ask for more memory from the kernel when the pool runs dry. However, s...