从多个数据框的列表中提取特定的列，并将它们组合成r中的新数据框

Question

How do I extract specific column of multiple dataframs of a list for example the 8th column of all dfs and combine the extracted columns into a new data frame.

I am using a for loop that does not give me the desired output. I prefer to use lapply() function instead of for loops. Do you have any idea how can I do this?

new_df <- data.frame()

for(i in 1:length(list_of_dfs)){

    col_8 <- list_of_dfs[[i]][8]

    new.df[i] <- col_8
}

View(df)

Answer 1

You can use lapply and do.call to achieve that :

library(magrittr)
lapply(list_of_dfs,function(i) i[,8]) %>% do.call(cbind,.) %>% data.frame