标签： fasta

#BiocManager::install('seqinr')   # 如果没安装过这包，先安装
library(seqinr)
library(stringr)
fasta <- read.fasta(file = "C:\\Users\\zhang\\Desktop\\Zea_mays.AGPv4.dna.chromosome.1.fa",
    as.string = TRUE,
    forceDNAtolower = FALSE)   # 修改上面的路径，fasta格式文件
class(fasta)

a1 <- fasta[[2]][1]   # 这里的[1]不用改，[[2]]表示排在第二的染色体，玉米中是2号染色体
str(a1)
a1 <- strsplit(a1,"")
str(a1)
b <- read.table("clipboard",header=F)   # 从excel复制需要的染色体位置信息
# b <- c(1,2,3,4,5)
k <- data.frame(1:nrow(b))
for (i in 1:nrow(b)){
    txt <- paste0("k[",i,",1] <- a1[[1]][as.numeric(b[",i,",1])]")
    eval(parse(text=txt))
}

write.table(k,"C:\\Users\\zhang\\Desktop\\123.txt",row.names=F,col.names=F,sep="\t",quote=F)