样本数据

Question

我有一个包含一列的数据框，我想根据第一列中的某些条件创建另一列。这是我到目前为止编写的脚本，它可以正常工作，但它很慢，因为它有大约5万行。

 data <- read.table("~/Documents/git_repos/Aspen/Reference_genome/Potrs01-genome_mod_id.txt")
> dim(data) # [1] 509744      1
> head(data)
           V1
1 Potrs000004
2 Potrs000004
3 Potrs000004
4 Potrs000004
5 Potrs000004
6 Potrs000004

test <- paste("Potrs00000", seq(000001,10000,by=1), sep ="")
length(test) # [1] 10000
> head(test)
[1] "Potrs000001" "Potrs000002" "Potrs000003" "Potrs000004" "Potrs000005"
[6] "Potrs000006"

test.m <- matrix("NA", nrow = 509744, ncol = 2 )
dim(test.m) # [1] 509744      2
> head(test.m)
     [,1] [,2]
[1,] "NA" "NA"
[2,] "NA" "NA"
[3,] "NA" "NA"
[4,] "NA" "NA"
[5,] "NA" "NA"
[6,] "NA" "NA"

 for (i in test) {
   for (j in data$V1) {
     if (i == j)
       test.m[,1] = j
       test.m[,2] = "chr9"
      }
    }
test.d <- as.data.frame(test.m)
> head(test.d)
           V1   V2
1 Potrs000004 chr9
2 Potrs000004 chr9
3 Potrs000004 chr9
4 Potrs000004 chr9
5 Potrs000004 chr9
6 Potrs000004 chr9

有没有办法修改代码以加快速度？

Answer 1

您似乎希望V1的{{1}}值与data中的元素匹配。

我会使用test执行此操作：

data.table

请注意，结果已经是library(data.table) setDT(data) data[,.(V1[V1 %in% test], "chr9")]（也是data.table）

样本数据

data.frame

如何在R中快速添加基于某些条件的列？

1 个答案:

样本数据