Obtaining summary statistics from unique column combinations in R

Question

I have a file input.txt that I read in as a data frame, and I need to be able to get summary statistics from it as shown in "output". Each ID in the file is unique, the Year and Status are not.

>input
ID  Year    Status
1   2002    OK
2   2002    OK
3   2003    NO
4   2003    OK
5   2007    OK
6   2007    NO

I've tried to use:

table(melt(input, id=c("ID"))

I'm still not getting what I would like. Below is the desired output I would like to get. I need to get the summary of individuals per year that had status OK and NO.

>output 
Year   OK   NO
2002    2   0
2003    1   1
2007    1   1

Can someone please help?

Answer 1

You may try this:

with(df, table(Year, Status))
#       Status
# Year   NO OK
#   2002  0  2
#   2003  1  1
#   2007  1  1

# or 
library(reshape2)
dcast(df, Year ~ Status)

#   Year NO OK
# 1 2002  0  2
# 2 2003  1  1
# 3 2007  1  1