r - 在R中将十进制转换为二进制？

Question

在 R 中将数字转换为基数 2(在字符串中，例如 5 将转换为 "0000000000000101")的最简单方法是什么？有intToBits ，但它返回一个字符串向量而不是一个字符串:

> intToBits(12)
 [1] 00 00 01 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[26] 00 00 00 00 00 00 00

我尝试了一些其他功能，但没有成功:

> toString(intToBits(12))
[1] "00, 00, 01, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00"

Answer 1

请注意 intToBits()返回“原始”向量，而不是字符向量(字符串)。请注意，我的回答是 @nico's original answer 的轻微扩展从每个位中删除前导“0”:

paste(sapply(strsplit(paste(rev(intToBits(12))),""),`[[`,2),collapse="")
[1] "00000000000000000000000000001100"

为了清楚起见，分解步骤:

# bit pattern for the 32-bit integer '12'
x <- intToBits(12)
# reverse so smallest bit is first (little endian)
x <- rev(x)
# convert to character
x <- as.character(x)
# Extract only the second element (remove leading "0" from each bit)
x <- sapply(strsplit(x, "", fixed = TRUE), `[`, 2)
# Concatenate all bits into one string
x <- paste(x, collapse = "")
x
# [1] "00000000000000000000000000001100"

或者，如 @nico showed ，我们可以使用 as.integer()作为从每个位中删除前导零的更简洁的方法。

x <- rev(intToBits(12))
x <- paste(as.integer(x), collapse = "")
# [1] "00000000000000000000000000001100"

只是为了方便复制粘贴，这里有一个上面的函数版本:

dec2bin <- function(x) paste(as.integer(rev(intToBits(x))), collapse = "")