Message-ID: <alpine.BSF.2.00.1312132228050.67315@pedal.dcn.davis.ca.us>
Date: 2013-12-14T06:40:44Z
From: Jeff Newmiller
Subject: Converting decimal to binary in R
In-Reply-To: <tencent_6AD3882132EDA8B24335FC09@qq.com>
On Sat, 14 Dec 2013, ???????? wrote:
> i have write a function to convert decimal number into binary number in R.
>
> dectobin<-function(x){
> as.numeric(intToBits(x))->x1
> paste(x1,collapse="")->x2
> as.numeric(gsub("0+$","",x2))->x3
> return(as.character(x3))}
>
> dectobin can get right result ,it is so long ,is there a build-in
> function to do ?
I don't know of one. The below function is roughly twice as fast as yours
and it works on an entire vector of values at once (but it still uses a
for loop to do so).
decToBinStr <- function(x) {
l <- floor( log( x, 2 ) ) + 1
v <- as.logical( intToBits( x ) )
vc <- rep( "0", length( v ) )
vc[ v ] <- "1"
m <- matrix( vc, ncol=length( x ) )
result <- rep( NA, length( x ) )
for ( idx in seq.int( length( x ) ) ) {
result[ idx ] <- paste( m[ seq.int( l[ idx ], 1 ), idx ], collapse="" )
}
result
}
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