问题描述
R 中一个令人难以置信的基本问题，但解决方案尚不清楚.
An incredibly basic question in R yet the solution isn't clear.
如何将字符向量拆分为单个字符，即 paste(..., sep='') 或 stringr::str_c() ?
How to split a vector of character into its individual characters, i.e. the opposite of paste(..., sep='') or stringr::str_c() ?
任何不那么笨重的东西:
Anything less clunky than this:
sapply(1:26, function(i) { substr("ABCDEFGHIJKLMNOPQRSTUVWXYZ",i,i) } )
"A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" "V" "W" "X" "Y" "Z"
是否可以通过其他方式进行，例如用 strsplit()、stringr::* 还是别的什么?
Can it be done otherwise, e.g. with strsplit(), stringr::* or anything else?
推荐答案
是的，strsplit 会做到的.strsplit 返回一个列表，因此您可以使用 unlist 将字符串强制转换为单个字符向量，或者使用列表索引 [[1]] 访问第一个元素.
Yes, strsplit will do it. strsplit returns a list, so you can either use unlist to coerce the string to a single character vector, or use the list index [[1]] to access first element.
x <- paste(LETTERS, collapse = "")
unlist(strsplit(x, split = ""))
# [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"
OR(注意实际上没有必要命名 split 参数)
OR (noting that it is not actually necessary to name the split argument)
strsplit(x, "")[[1]]
# [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"
您也可以拆分 NULL 或 character(0) 以获得相同的结果.
You can also split on NULL or character(0) for the same result.
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