Combine data in many row into a columnn

Question

I have a data like this:

  year  Male
1 2011    8
2 2011    1
3 2011    4
4 2012    3
5 2012    12
6 2012    9
7 2013    4
8 2013    3
9 2013    3

and I need to group the data for the year 2011 in one column, 2012 in the next column and so on.

   2011  2012  2013
1   8     3     4 
2   1    12     3
3   4     9     3

How do I achieve this?

Answer 1

One option is unstack if the number of rows per 'year' is the same

unstack(df1, Male ~ year)

Answer 2

One option is to use functions from dplyr and tidyr.

library(dplyr)
library(tidyr)

dt2 <- dt %>%
  group_by(year) %>%
  mutate(ID = 1:n()) %>%
  spread(year, Male) %>%
  select(-ID)