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The Org Mode 7 Reference Manual
by Carsten Dominik and others
Paperback (6"x9"), 282 pages
ISBN 9781906966089
RRP £9.95 ($14.95)

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15.1 References

To compute fields in the table from other fields, formulas must reference other fields or ranges. In Org, fields can be referenced by name, by absolute coordinates, and by relative coordinates. To find out what the coordinates of a field are, press C-c ? in that field, or press C-c } to toggle the display of a grid.

Field references

Formulas can reference the value of another field in two ways. Like in any other spreadsheet, you may reference fields with a letter/number combination like B3, meaning the 2nd field in the 3rd row.

Org also uses another, more general operator that looks like this:

@row$column

Column references can be absolute like ‘1’, ‘2’,...N, or relative to the current column like ‘+1’ or ‘-2’.

The row specification only counts data lines and ignores horizontal separator lines (hlines). You can use absolute row numbers ‘1’...N, and row numbers relative to the current row like ‘+3’ or ‘-1’. Or specify the row relative to one of the hlines: ‘I’ refers to the first hline,(129) ‘II’ to the second, etc. ‘-I’ refers to the first such line above the current line, ‘+I’ to the first such line below the current line. You can also write ‘III+2’ which is the second data line after the third hline in the table.

‘0’ refers to the current row and column. Also, if you omit either the column or the row part of the reference, the current row/column is implied.

Org's references with unsigned numbers are fixed references in the sense that if you use the same reference in the formula for two different fields, the same field will be referenced each time. Org's references with signed numbers are floating references because the same reference operator can reference different fields depending on the field being calculated by the formula.

As a special case, references like ‘$LR5’ and ‘$LR12’ can be used to refer in a stable way to the 5th and 12th field in the last row of the table.

Here are a few examples:

@2$3      2nd row, 3rd column
C2        same as previous
$5        column 5 in the current row
E&        same as previous
@2        current column, row 2
@-1$-3    the field one row up, three columns to the left
@-I$2     field just under hline above current row, column 2

Range references

You may reference a rectangular range of fields by specifying two field references connected by two dots ‘..’. If both fields are in the current row, you may simply use ‘$2..$7’, but if at least one field is in a different row, you need to use the general @row$column format at least for the first field (i.e the reference must start with ‘@’ in order to be interpreted correctly). Examples:

$1..$3        First three fields in the current row.
$P..$Q        Range, using column names (see under Advanced)
@2$1..@4$3    6 fields between these two fields.
A2..C4        Same as above.
@-1$-2..@-1   3 numbers from the column to the left, 2 up to current row

Range references return a vector of values that can be fed into Calc vector functions. Empty fields in ranges are normally suppressed, so that the vector contains only the non-empty fields (but see the ‘E’ mode switch below). If there are no non-empty fields, ‘[0]’ is returned to avoid syntax errors in formulas.

Field coordinates in formulas

For Calc formulas and Lisp formulas @# and $# can be used to get the row or column number of the field where the formula result goes. The traditional Lisp formula equivalents are org-table-current-dline and org-table-current-column. Examples:

if(@# % 2, $#, string(""))   column number on odd lines only
$3 = remote(FOO, @@#$2)      copy column 2 from table FOO into
                             column 3 of the current table

For the second example, table FOO must have at least as many rows as the current table. Note that this is inefficient(130) for large number of rows.

Named references

‘$name’ is interpreted as the name of a column, parameter or constant. Constants are defined globally through the variable org-table-formula-constants, and locally (for the file) through a line like

#+CONSTANTS: c=299792458. pi=3.14 eps=2.4e-6

Also properties (see section 7 Properties and columns) can be used as constants in table formulas: for a property ‘:Xyz:’ use the name ‘$PROP_Xyz’, and the property will be searched in the current outline entry and in the hierarchy above it. If you have the ‘constants.el’ package, it will also be used to resolve constants, including natural constants like ‘$h’ for Planck's constant, and units like ‘$km’ for kilometers.(131) Column names and parameters can be specified in special table lines. These are described below, see section 15.8 Advanced features. All names must start with a letter, and further consist of letters and numbers.

Remote references

You may also reference constants, fields and ranges from a different table, either in the current file or even in a different file. The syntax is

remote(NAME-OR-ID,REF)

where NAME can be the name of a table in the current file as set by a #+TBLNAME: NAME line before the table. It can also be the ID of an entry, even in a different file, and the reference then refers to the first table in that entry. REF is an absolute field or range reference as described above for example @3$3 or $somename, valid in the referenced table.

ISBN 9781906966089The Org Mode 7 Reference ManualSee the print edition