A very complex way of not adding the extra column: | name | a | b | c | |------+----+---+---| | foo | 1 | 2 | 3 | | bar | 3 | 2 | 1 | | bar | 4 | 5 | 6 | |------+----+---+---| | | 7 | | | #+TBLFM: @5$2='(apply '+ (mapcar* (lambda(x y) (if (string= x "bar") y 0)) '(@i$...@ii$1) '(@i$...@ii$2)));L
* the two arguments at the end are the name and a columns: '(foo bar bar) and '(1 3 4) * the lambda function returns the second argument if first is "bar", 0 otherwise. * mapcar* applies the lambda function to arguments from the 2 lists. * apply '+ adds the resulting list Regards, .j. On Tue, Sep 07, 2010 at 12:44:03AM +0200, Christian Moe wrote: > On 9/6/10 3:38 PM, Inquisitive Scientist wrote: > > > 2. How do I compute the sum of a column only if a corresponding row > >matches some condition? For example, how do I compute the sum of > >numbers in column a for which the name in column "name" is "bar"? For > >example, I should get 7 for the sum in column a in the table below: > > > >| name | a | b | c | > >|------+---+---+---| > >| foo | 1 | 2 | 3 | > >| bar | 3 | 2 | 1 | > >| bar | 4 | 5 | 6 | > >|------+---+---+---| > > Here's one way: Add a new row after the first, as below. Then run C-c > C-c on the formula line: > > | name | | a | b | c | > |------+---+---+---+---| > | foo | | 1 | 2 | 3 | > | bar | | 3 | 2 | 1 | > | bar | | 4 | 5 | 6 | > |------+---+---+---+---| > | | | | | | > #+TBLFM: $2='(if (string= $1 "bar") 1 0):: > @5$3=vsum(vmask(@i$...@ii$2,@i...@ii)) > > It does exactly what you asked, but I don't think it will scale well... > _______________________________________________ Emacs-orgmode mailing list Please use `Reply All' to send replies to the list. Emacs-orgmode@gnu.org http://lists.gnu.org/mailman/listinfo/emacs-orgmode