# arguments
fp <- "RNA 2018_06_17 4_37_03.tsv" # ファイルパス
smp <- c("young_leaf_1", "young_leaf_2", "matured_leaf_1", "matured_leaf_2") # サンプル名

# parse tsv
ndrop <- readLines(fp)
st <- grep("サンプル", ndrop)
ed <- c((st-1)[-1], length(ndrop))
res <- mapply(function(x,y){ndrop[x:y]}, st, ed)

lst_al <- lapply(seq_along(res), function(i){
	x <- res[[i]]
	x[nchar(x)!=0] %>%
	.[-1:-grep("//QSpecEnd:", .)] %>%
	strsplit(., "\t") %>% data.frame(.) %>%
	t() %>%
	data.frame(., row.names=NULL, stringsAsFactors=F) %>%
	setNames(., c("wave_length", smp[i]))
})

dat <- Reduce(function(x,y){merge(x,y, by="wave_length")}, lst_al) %>%
	 tidyr::gather(., key="sample", value="absorbance", -1) %>%
	mutate_at(vars(c(1,3)), funs(as.numeric))

# plot
ggplot(dat, aes(x=wave_length, y=absorbance, colour=sample)) + geom_line()