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Aggregate / summarize multiple variables per group (e.g. sum, mean)
...-date), sum)
# summarising a specific set of non-grouping variables using select_helpers
# see ?select_helpers for more options
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(starts_with('x')), sum)
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(matches('.*...
How to create a video from images with FFmpeg?
...
-pattern_type glob
This great option makes it easier to select the images in many cases.
Slideshow video with one image per second
ffmpeg -framerate 1 -pattern_type glob -i '*.png' \
-c:v libx264 -r 30 -pix_fmt yuv420p out.mp4
Add some music to it, cutoff when the presumably...
HQL ERROR: Path expected for join
...
select u from UserGroup ug inner join ug.user u
where ug.group_id = :groupId
order by u.lastname
As a named query:
@NamedQuery(
name = "User.findByGroupId",
query =
"SELECT u FROM UserGroup ug " +
"INNER JOIN...
Pick any kind of file via an Intent in Android
...
how can I get the selected file ? I guess it's the path, but how ?
– Francisco Corrales Morales
Nov 26 '14 at 17:31
1
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Save all files in Visual Studio project as UTF-8
...inal reference being defaced by spam site.
Short version: edit one file, select File -> Advanced Save Options. Instead of changing UTF-8 to Ascii, change it to UTF-8. Edit: Make sure you select the option that says no byte-order-marker (BOM)
Set code page & hit ok. It seems to persist just...
Is there a way to do repetitive tasks at intervals?
...(5 * time.Second)
quit := make(chan struct{})
go func() {
for {
select {
case <- ticker.C:
// do stuff
case <- quit:
ticker.Stop()
return
}
}
}()
You can stop the worker by closing the quit channel: close(quit).
...
How do I grep recursively?
...
@lorniper it makes the shell select all files and folders in your current directory, making in turn the grep apply to those files and (recursively because of the -R option) to the folders.
– VonC
Aug 4 '16 at 7:10
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Why doesn't await on Task.WhenAll throw an AggregateException?
...
Excellent clear answer, this should IMO be the selected one.
– bytedev
Feb 22 '18 at 17:16
3
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Cordova: start specific iOS emulator image
...t the simulator before launching a different target simulator (On Menu bar select Simulator->Quit)
Take into account that you may need to quit the iOS simulator via menu to switch from 3.5 to 4 inch iPhone.
dynamic list is available in platforms/ios/cordova/lib/list-emulator-images
...
Is there a string math evaluator in .NET?
...riptControl is a COM object. In the "Add reference" dialog of the project select the "COM" tab and scroll down to "Microsoft Script Control 1.0" and select ok.
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