分為3個字符長度

Question

我有一個非常簡單的問題：如何在單個代碼中將以下文本分為3個

mycodes <- c("ATTTGGGCTAATTTTGTTTCTTTCTGGGTCTCTC")
strsplit(mycodes, split = character(3), fixed = T, perl = FALSE, useBytes = FALSE)

[[1]]
 [1] "A" "T" "T" "T" "G" "G" "G" "C" "T" "A" "A" "T" "T" "T" "T" "G" "T" "T" "T" "C"
[21] "T" "T" "T" "C" "T" "G" "G" "G" "T" "C" "T" "C" "T" "C"

這不是我想要的； 我一次要三個字母：

[1] "ATT"  "TGG", "GCT"...............and so on the final may be of one, two or three letters depending upon the letter availability.

謝謝;

Answer 1

我認為您想使用密碼子。 如果是這樣，您可能需要查看Bioconductor提供的Biostrings軟件包。 它提供了用於處理生物序列數據的多種工具。

library(Biostrings)
?codons

您可以通過一點笨拙的強制實現您想要的：

as.character(codons(DNAString(mycodes)))

Answer 2

這是使用stringr包的一種方法

require(stringr)
start = seq(1, nchar(mycodes), 3)
stop  = pmin(start + 2, nchar(mycodes))
str_sub(mycodes, start, stop)

輸出是

[1] "ATT" "TGG" "GCT" "AAT" "TTT" "GTT" "TCT" "TTC" "TGG"
[10] "GTC" "TCT" "C" 

Answer 3

您還可以使用：

 strsplit(data, '(?<=.{3})', perl=TRUE)
[[1]]
 [1] "ATT" "TGG" "GCT" "AAT" "TTT" "GTT" "TCT" "TTC" "TGG" "GTC" "TCT" "C" 

要么

library(stringi)
stri_extract_all_regex(data, '.{1,3}')