3.5.10 Advanced features

If you want the recalculation of fields to happen automatically, or if you want to be able to assign names²² to fields and columns, you need to reserve the first column of the table for special marking characters.

C-# (org-table-rotate-recalc-marks)

Rotate the calculation mark in first column through the states ‘#’, ‘*’, ‘!’, ‘$’. When there is an active region, change all marks in the region.

Here is an example of a table that collects exam results of students and makes use of these features:

|---+---------+--------+--------+--------+-------+------|
|   | Student | Prob 1 | Prob 2 | Prob 3 | Total | Note |
|---+---------+--------+--------+--------+-------+------|
| ! |         |     P1 |     P2 |     P3 |   Tot |      |
| # | Maximum |     10 |     15 |     25 |    50 | 10.0 |
| ^ |         |     m1 |     m2 |     m3 |    mt |      |
|---+---------+--------+--------+--------+-------+------|
| # | Peter   |     10 |      8 |     23 |    41 |  8.2 |
| # | Sam     |      2 |      4 |      3 |     9 |  1.8 |
|---+---------+--------+--------+--------+-------+------|
|   | Average |        |        |        |  25.0 |      |
| ^ |         |        |        |        |    at |      |
| $ | max=50  |        |        |        |       |      |
|---+---------+--------+--------+--------+-------+------|
#+TBLFM: $6=vsum($P1..$P3)::$7=10*$Tot/$max;%.1f::$at=vmean(@-II..@-I);%.1f

Important: Please note that for these special tables, recalculating the table with C-u C-c * only affects rows that are marked ‘#’ or ‘*’, and fields that have a formula assigned to the field itself. The column formulas are not applied in rows with empty first field.

The marking characters have the following meaning:

‘!’

The fields in this line define names for the columns, so that you may refer to a column as ‘$Tot’ instead of ‘$6’.

‘^’

This row defines names for the fields above the row. With such a definition, any formula in the table may use ‘$m1’ to refer to the value ‘10’. Also, if you assign a formula to a names field, it is stored as ‘$name = ...’.

‘_’

Similar to ‘^’, but defines names for the fields in the row below.

‘$’

Fields in this row can define parameters for formulas. For example, if a field in a ‘$’ row contains ‘max=50’, then formulas in this table can refer to the value 50 using ‘$max’. Parameters work exactly like constants, only that they can be defined on a per-table basis.

‘#’

Fields in this row are automatically recalculated when pressing TAB or RET or S-TAB in this row. Also, this row is selected for a global recalculation with C-u C-c *. Unmarked lines are left alone by this command.

‘*’

Selects this line for global recalculation with C-u C-c *, but not for automatic recalculation. Use this when automatic recalculation slows down editing too much.

‘/’

Do not export this line. Useful for lines that contain the narrowing ‘<N>’ markers or column group markers.

Finally, just to whet your appetite for what can be done with the fantastic Calc package, here is a table that computes the Taylor series of degree n at location x for a couple of functions.

|---+-------------+---+-----+--------------------------------------|
|   | Func        | n | x   | Result                               |
|---+-------------+---+-----+--------------------------------------|
| # | exp(x)      | 1 | x   | 1 + x                                |
| # | exp(x)      | 2 | x   | 1 + x + x^2 / 2                      |
| # | exp(x)      | 3 | x   | 1 + x + x^2 / 2 + x^3 / 6            |
| # | x^2+sqrt(x) | 2 | x=0 | x*(0.5 / 0) + x^2 (2 - 0.25 / 0) / 2 |
| # | x^2+sqrt(x) | 2 | x=1 | 2 + 2.5 x - 2.5 + 0.875 (x - 1)^2    |
| * | tan(x)      | 3 | x   | 0.0175 x + 1.77e-6 x^3               |
|---+-------------+---+-----+--------------------------------------|
#+TBLFM: $5=taylor($2,$4,$3);n3