diff options
| -rw-r--r-- | r.html.markdown | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/r.html.markdown b/r.html.markdown index cd09e8da..f6a62ae6 100644 --- a/r.html.markdown +++ b/r.html.markdown @@ -516,8 +516,8 @@ students[,order(c("name","year","house","houseFounderName")), with=F] # 6: Draco 0 S Salazar # data.table makes summary tables easy +students[,sum(year),by=house] # => -# students[,sum(year),by=house] # house V1 # 1: G 3 # 2: H 3 |