是否有一个函数可以在 R 中创建重复的字母列表？
就像是
letters[1:30]
[1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
[20] "t" "u" "v" "w" "x" "y" "z" NA NA NA NA
但不是 NA，我希望输出继续 aa, bb, cc, dd ...
最佳答案
拼凑一个快速函数来做这样的事情并不难:
myLetters <- function(length.out) {
a <- rep(letters, length.out = length.out)
grp <- cumsum(a == "a")
vapply(seq_along(a),
function(x) paste(rep(a[x], grp[x]), collapse = ""),
character(1L))
}
myLetters(60)
# [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l"
# [13] "m" "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x"
# [25] "y" "z" "aa" "bb" "cc" "dd" "ee" "ff" "gg" "hh" "ii" "jj"
# [37] "kk" "ll" "mm" "nn" "oo" "pp" "qq" "rr" "ss" "tt" "uu" "vv"
# [49] "ww" "xx" "yy" "zz" "aaa" "bbb" "ccc" "ddd" "eee" "fff" "ggg" "hhh"
关于字母的重复向量，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21681785/