Table columns

Package: TABLES_PACKAGE. Registered by createEngine(); for a slimmer engine, register it explicitly (see choosing packages).

A markdown table is otherwise the one block the engine reads and skips, so the numbers in it cannot be totalled from where they sit. A column can be named and read as data instead:

Expression	Meaning
sum of column "cost" in table above	the total of the named column
average of column "cost" above	the mean of the named column
min of column "cost" above	the smallest cell
max of column "cost" above	the largest cell
count of column "cost" above	how many numeric cells it has
median of column "cost" above	the middle cell
standard deviation of column "cost" above	how spread out it is
variance of column "cost" above	the squared spread
spread of column "cost" above	largest minus smallest
mode of column "cost" above	the most frequent cell

total of column and mean of column are accepted as synonyms of sum and average. The address is optional: with only the nearest table to read from, sum of column "cost", sum of column "cost" above, and sum of column "cost" in table above all mean the same thing.

The table’s rows must start with a pipe, and the header needs a |---| separator under it. Every summary form the table above names, read from the same column:

| item | cost |
| ---- | ---- |
| rent | 1200 |
| food |  300 |
| taxi |   12 |

sum of column "cost" in table above     // 1,512
average of column "cost" above          // 504
min of column "cost" above              // 12
max of column "cost" above              // 1,200
count of column "cost" above            // 3
median of column "cost" above           // 300

The spread and shape aggregates read a column too, so a table of readings can be summarised where it sits:

| reading | score |
| ------- | ----- |
| a       |     2 |
| b       |     4 |
| c       |     4 |
| d       |     4 |
| e       |     5 |
| f       |     5 |
| g       |     7 |
| h       |     9 |

standard deviation of column "score" above  // 2
variance of column "score" above            // 4
spread of column "score" above              // 7
mode of column "score" above                // 4

The column name is matched case-insensitively. A cell that is not a plain number, a label, a blank, or a currency or unit value, is skipped rather than counted, so a stray row does not break an otherwise-numeric column. A column with no numbers at all, or a name that is not one of the headers, is a clear error rather than a silent zero.

Currency and unit cells are not read yet, and a table whose rows do not start with a pipe is not recognised. Both are deliberately left for a later slice.

Like line references, a column read only works inside a document, since it reads a table elsewhere in the note.