将数据框的列名或从 R 对象添加到另一个数据框

Question

I'm currently working with a huge count matrix issued of single cell sequencing ...

So, in order to analyze them with R and my 8 Gb of RAM, I had to split it in several sub-matrices.

I simply used split in order to do that so I loose the heathers of the matrix.

So, I would like to add them back with R or find a better way to split them more efficiently.

My questions are:

1. If a have an object called heathers with all the column names stocked inside, is there a way to efficiently add this object to a dataframe? I tried rbind but it doesn't really solve the problem.

2. Is there a better way to cut those huge count matrices into multiple parts? (I can't do it through R because I don't have enough RAM, R crashes if I try to import the whole matrix)

Answer 1

You can access and mutate a data.frame s column names with the names function:

df <- data.frame(foo = 1:5, bar = 6:10, opt = 11:15)

original_names <- names(df)


original_names 

Returns:

[1] "foo" "bar" "opt"

And to assign new names:

names(df) <- c("new_col1", "new_col2", "new_col3")

Now:

df

Returns:

  new_col1 new_col2 new_col3
1        1        6       11
2        2        7       12
3        3        8       13
4        4        9       14
5        5       10       15

And to 'undo' the renaming:

names(df) <- original_names

And df has again its original names:

  foo bar opt
1   1   6  11
2   2   7  12
3   3   8  13
4   4   9  14
5   5  10  15

Answer 2

1. If a have an object called heathers with all the column names stocked inside, is there a way to efficiently add this object to a dataframe? I tried rbind but it doesn't really solve the problem.

You can add headers to a dataframe like this:

dataframe <- data.frame(c("a", "b","c"),
                        c("d", "e", "f"))

headers <- c("header_1" , "header_2")

names(dataframe) <- headers

dataframe

  header_1 header_2
1        a        d
2        b        e
3        c        f

2. You could use bash for such tasks.