将一列作为数据框列表添加到数据框

Question

Just wondering how can I add a new column to an existing data frame which is a list of data frames. For example, if I have a data frame like so:-

x <- data.frame("SN" = 1:2, "Age" = c(21,15), "Name" =
c("John","Dora"))

I need to add a new column to it say 'test' - which I can realize by

x$test <- 1

But this adds a new column as a numeric column.

I need this column such that the element in each row of this column in this data frame is a list of say three (3) data frames. Each of these 3 data frame in a row will contain different number of rows and columns. Similar data frames in other rows will contain same number type of columns but can have different number of rows.

Like this:-

x$test[1] <- list(df1_1, df1_2, df1_3)
x$test[2] <- list(df2_1, df2_2, df2_3)

where df1_1, df1_2, df1_3 are independent data frames with different number of columns and rows in row 1 and df2_1, df2_2, df2_3_3 are independent data frames with different number of columns and rows in row 2.

The number of columns and the data type of these columns of df1_1 and df2_1 are the same. Similarly, the number of columns and the data type of these columns of df1_2 and df2_2 are the same and so on.

Is there a way to do so?

The generation of the data frames df1_1, df1_2, df1_3 are done through a loop.

Any pointers/suggestions shall be highly valued.

Best regards

Deepak Agarwal

Answer 1

We could get the datasets into a list with mget

# // initialize a list column
x$test <- vector('list', nrow(x))
# // loop over the sequence of rows of dataset
for(i in seq_len(nrow(x))) {
     # // create string with index
     str1 <- paste0('df', i, '_', 1:3)
     # // get the value of the objects from string with mget
     tmplist <- mget(str1)
     # // assign it to the corresponding list element of test
     x$test[[i]] <- tmplist
  }