大约有 47,000 项符合查询结果（耗时：0.0579秒） [XML]
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...
How do you maintain development code and production code? [closed]
...ready to be deployed into production at any time: the next release, with a selected set of feature branches merged in master.
dev (or integration branch, or 'next') is the one where the feature branch selected for the next release are tested together
maintenance (or hot-fix) branch is the one for th...
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...
Auto-fit TextView for Android
...didn't remove the getMaxLines() and used your own. it will still work only from API16... please change it so that everyone could use it. i suggest to override setMaxLines to store the parameter to a field and then access the field instead of using getMaxLines.
– android develop...
Android ListView headers
...ms) {
super(context, 0, items);
mInflater = LayoutInflater.from(context);
}
@Override
public int getViewTypeCount() {
return RowType.values().length;
}
@Override
public int getItemViewType(int position) {
return getItem(position).getViewType...
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
...
How do I prevent 'git diff' from using a pager?
...ent variable is set, Git does not change it at all).
If you want to selectively override Git's default setting for LESS, you can set core.pager to e.g. less -+S.
This will be passed to the shell by Git, which will translate the final command to LESS=FRSX less -+S. The environment tells the ...
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
...
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...