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Can dplyr package be used for conditional mutating?
... ifelse(a == 0 | a == 1 | a == 4 | a == 3 | c == 4, 3, NA)))
Added - if_else: Note that in dplyr 0.5 there is an if_else function defined so an alternative would be to replace ifelse with if_else; however, note that since if_else is stricter than ifelse (both legs of the condition must have the ...
What is the easiest way to remove the first character from a string?
... fastest and most readable way of doing things:
require 'benchmark'
N = 1_000_000
puts RUBY_VERSION
STR = "[12,23,987,43"
Benchmark.bm(7) do |b|
b.report('[0]') { N.times { "[12,23,987,43"[0] = '' } }
b.report('sub') { N.times { "[12,23,987,43".sub(/^\[+/, "") } }
b.report('gsub') { N.ti...
how to read value from string.xml in android?
...
Try this
String mess = getResources().getString(R.string.mess_1);
UPDATE
String string = getString(R.string.hello);
You can use either getString(int) or getText(int) to retrieve a string. getText(int) will retain any rich text styling applied to the string.
Reference: https://dev...
Android应用开发性能优化完全分析 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...问题，下面和右侧都会提示你选择的帧相关详细信息或者alert信息），但是遗憾的是通过Systrace只能大体上发现是否存在性能问题，具体问题还需要通过Traceview或者代码中嵌入Trace工具类等去继续详细分析，总之很蛋疼。
PS：如...
Debug Error \"pure virtual function call\" 原因解析 - 更多技术 - 清泛...
...
public:
virtual void virtualFunc(){}
};
Base* pB = new Derived;
__try
{
delete pB; // . . . b)
pB = NULL;
}
__except(EXCEPTION_EXECUTE_HANDLER){
}
pB->virtualFunc(); // . . . c)
在b)处析构Derived对象的时候，在其基类析构函数中a)处抛出了...
iOS 7 - Status bar overlaps the view
...patibility.
NSUInteger DeviceSystemMajorVersion() {
static NSUInteger _deviceSystemMajorVersion = -1;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
NSString *systemVersion = [UIDevice currentDevice].systemVersion;
_deviceSystemMajorVersion = [[syste...
How to enable cURL in PHP / XAMPP
...
Since you're using XAMPP, uncomment the line
;extension=php_curl.dll
in xampp\apache\bin\php.ini, and then restart the Apache service.
NB: In newer XAMPP versions, PHP has moved to root xampp folder xampp\php\php.ini.
...
Getting LaTeX into R Plots
...t interferes with the ggplot ~ # tikzDecice combo
colnames(AR) <- c("$V_{BB}[V]$", "$V_{RB}[V]$" , "$V_{RC}[V]$" , "$I_B[\\mu A]$" , "IC" , "$V_{BE}[V]$" , "$V_{CE}[V]$" , "beta" , "$I_E[mA]$")
# make sure the working directory is where you want your tikz file to go
setwd("~/TexImageFolder/")
...
targetContentOffsetForProposedContentOffset:withScrollingVelocity without subclassing UICollectionVi
... velocity: CGPoint) -> CGPoint {
var offsetAdjustment = CGFloat.greatestFiniteMagnitude
let horizontalOffset = proposedContentOffset.x
let targetRect = CGRect(origin: CGPoint(x: proposedContentOffset.x, y: 0), size: self.collectionView!.bounds.size)
for layoutAttributes in super....
How to write to a file in Scala?
...re the main entry points into the Scala IO File API.
import scalax.io._
val output:Output = Resource.fromFile("someFile")
// Note: each write will open a new connection to file and
// each write is executed at the begining of the file,
// so in this case the last write will be th...