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data.table vs dplyr: can one do something well the other can't or does poorly?
..., keyby = .(x,y)][DT2][, z := z*mul][]
# dplyr equivalent
DF1 %>% group_by(x, y) %>% summarise(z = sum(z)) %>%
right_join(DF2) %>% mutate(z = z * mul)
2) do it all in one go (using by = .EACHI feature):
DT1[DT2, list(z=sum(z) * mul), by = .EACHI]
What is the advantage?
We do...
CursorLoader usage without ContentProvider
... Found a nice code example that uses this - bitbucket.org/ssutee/418496_mobileapp/src/fc5ee705a2fd/demo/… - found it very useful !
– Shushu
May 20 '12 at 21:17
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Change case of a file on Windows?
...o do this in bulk? e.g. with powershell, Get-ChildItem '.' | Rename-Item {$_.Name.ToLowerCase()}
– killjoy
Nov 4 '18 at 1:23
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What is a semaphore?
...interestingly it has already been used: albahari.com/threading/part2.aspx#_Semaphore
– Igor Brejc
Mar 27 '15 at 8:50
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Usage of EnsureSuccessStatusCode and handling of HttpRequestException it throws
... HttpClient())
{
...
response = await client.PostAsync(_url, context);
response.EnsureSuccesStatusCode();
...
}
}
The Exception thrown on GetUserIdAsync will be handled on DoSomethingAsync.
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How do I launch the Android emulator from the command line?
...
emulator -avd @name-of-your-emulator
where emulator is under:
${ANDROID_SDK}/tools/emulator
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Preferred Github workflow for updating a pull request after code review
...uming that no-one cares because it is a fork.
– brita_
Feb 7 '15 at 11:02
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Follow-up: best pract...
How to deal with persistent storage (e.g. databases) in Docker
...te --name hello
docker run -d -v hello:/container/path/for/volume container_image my_command
This means that the data-only container pattern must be abandoned in favour of the new volumes.
Actually the volume API is only a better way to achieve what was the data-container pattern.
If you create ...
Should I store entire objects, or pointers to objects in containers?
...ality, for example using placement new (see en.wikipedia.org/wiki/Placement_syntax#Custom_allocators).
– amit
Feb 27 '11 at 11:34
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How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?
... @MaxGontar, your mysql solution rocks, thx. what if in your @_TestTable you remove row#1>: SELECT 1, 10, '2009-03-04', 'john', 399 , this is, what if you have a single row for a given home value? thx.
– egidiocs
Nov 11 '11 at 3:44
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