大约有 19,300 项符合查询结果（耗时：0.0279秒） [XML]
Getting and removing the first character of a string
...ng(x, 1, 1)
## [1] "h"
substring(x, 2)
## [1] "ello stackoverflow"
The idea of having a pop method that both returns a value and has a side effect of updating the data stored in x is very much a concept from object-oriented programming. So rather than defining a pop function to operate on chara...
setNeedsLayout vs. setNeedsUpdateConstraints and layoutIfNeeded vs updateConstraintsIfNeeded
...read about autolayouts–says:
If something changes later on that invalidates one of your constraints, you should remove the constraint immediately and call setNeedsUpdateConstraints. In fact, that’s the only case where you should have to trigger a constraint update pass.
In addition, in my ...
MIME type warning in chrome for png images
...S Express and confirmed the warning went away.
– patridge
May 26 '11 at 18:16
...
How to duplicate a git repository? (without forking)
...
@Thomas I just did this and yes, it preserved all of my history in the copy. Note that after you push and cd into the new repo, there's still nothing there because you've pushed to the remote, so you need to do a pull
–...
How to subtract a day from a date?
... Python datetime object is timezone-aware than you should be careful to avoid errors around DST transitions (or changes in UTC offset for other reasons):
from datetime import datetime, timedelta
from tzlocal import get_localzone # pip install tzlocal
DAY = timedelta(1)
local_tz = get_localzone() ...
How to make overlay control above all other controls?
...
If you are using a Canvas or Grid in your layout, give the control to be put on top a higher ZIndex.
From MSDN:
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" WindowTitle="ZIndex Sample">
<Canvas>
<Rectangle ...
How do I edit an existing tag message in git?
...
The <tag name>^{} thing didn't work for me. After some searching I determined that this is a Windows thing: cmd.exe uses ^ as a shell escape, so you need to double it up.
– Karl Knechtel
Aug 13 at 16:13
...
Why would a post-build step (xcopy) occasionally exit with code 2 in a TeamCity build?
...
Even if you provide the /Y switch with xcopy, you'll still get an error when xcopy doesn't know if the thing you are copying is a file or a directory. This error will appear as "exited with code 2". When you run the same xcopy at a command p...
Dark theme in Netbeans 7 or 8
...now available in NetBeans 8.0 & 8.1!
The Real Thing
This plugin provides the real Darcula, not an imitation.
Konstantin Bulenkov of the JetBrains company open-sourced the Darcula look-and-feel originally built for the IntelliJ IDE. This NetBeans plugin discussed here wraps that original impl...
Simple calculations for working with lat/lon and km distance?
... probably want a more complicated formula using the WGS84 reference ellipsoid (the model used for GPS). But the error is probably negligible for your purposes.
Source: http://en.wikipedia.org/wiki/Latitude
Caution: Be aware that latlong coordinates are expressed in degrees, while the cos function...