01 library("lattice")
02 
03 commits <- read.csv("perl-git-log.csv")
04 
05 commits$year <- format(
06   as.POSIXlt(
07     commits$time, 
08     origin="1970-01-01"), 
09   "%Y"
10 )
11   # Authors with more than 5000 
12   # file commits
13 au=table(commits$author)
14 au = sort(subset( au, au > 5000 ))
15 
16 files.by.auth.year = 
17       table( commits$author, commits$year )
18 files.by.auth.year = 
19       as.data.frame( files.by.auth.year )
20 names( files.by.auth.year ) = 
21       c("author", "year", "files")
22 
23 files.by.auth.year = subset( 
24   files.by.auth.year,
25   files.by.auth.year$author %in% names(au)
26 )
27 
28 png(file="authors-by-year.png")
29 xyplot( files ~ year | author, 
30     data = files.by.auth.year, 
31     layout = c(1, 5), 
32     scales = list(x = list(rot = 45)), 
33     type = "l",
34     xlab = "Year",
35     ylab = "File Commits",
36     title = "Authors with > 5000 Commits"
37 )