Re: [Orgmode] questions about table mode and spreadsheets

[Juan]

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)) 
'(@address@hidden) '(@address@hidden)));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(@address@hidden,@address@hidden))
>
> It does exactly what you asked, but I don't think it will scale well...
>