在R中的不同数据集中删除多行

Question

I am working with multiple data.frames and I encountered problem when I want to delete specific rows in all of the data.frames . My problem is similar to the one posted here , but I cannot make it work on the rows:

lst <- list(dat1,dat2)
lapply(lst,`[`, !="A", TRUE)

Assuming my tables look like this and there are multiple row names so it is not possible to extract all but A by c("B", "C","D", ...) :

---

|   | 1 | 2 | 3 | 
|---|---|---|---|
| A |   |   |   | 
| B |   |   |   |
| A |   |   |   |

|   | 1 | 2 | 3 | 
|---|---|---|---|
| C |   |   |   | 
| A |   |   |   |
| A |   |   |   |

---

I would be grateful for any help! Thanks

Answer 1

If you want to use more complicated functions in an *apply call it's often useful or even necessary to use anonymous functions. The advantage is that you can build that function that is supposed to be applied to every list element (here, data.frames) just like you would do it in the case of a single data.frame.

If you wanted to subset rows of a regular data.frame by rownames you would use something like

mtcars[rownames(mtcars) != "Mazda RX4", ]

And in your lapply call you will do it the same way using an anonymous function where x represents each list element:

lapply(lst, function(x) x[rownames(x) != "A", ])