Function Names
table read column selected rowsDescription
This function extracts a column from the table and places the values in the set from the selected rows where the calculated expression returns true. All blank or non-existing entries will be translated to blank strings. Automatic type conversion (e.g. numbers to numerals) can be adjusted with the table configure() function.
Call as: function
Restrictions
Indirect parameter passing is disabled
This function provides a table context for partial table specifications with table name and row number for selected function parameters
Parameter count
3
Parameters
| No. | Type | Description |
|---|---|---|
| 1. input |
string | Name of existing table |
| 2. input |
table column | Existing column See table columns as function parameters for general ruling for this parameter.
|
| 3. code |
expression :string |
Expression to select rows Specify the conditions or rules to select the rows. See expressions to select rows. |
Return value
| Type | Description |
|---|---|
| set | Retrieved data Data from the different rows in the same column. |
Examples
table initialize ( table 1, { { Animal, leg count },
{ Worm, 0}, { Bird, 2 }, { Dog, 4 }, { Fly, 6 }, { Tick, 8 } } );
echo( table read column selected rows( table 1, Animal, [leg count]>4 ) );
echo( table read column selected rows( table 1, leg count, [leg count]>4 ) );
// Numbers are read as numerals. Force reading them as strings:
table configure( table 1, read numerals, no );
// Pay attention to convert leg counts into nuemrals here.
echo( table read column selected rows( table 1, leg count, num([leg count])>4 ) );Output
{'Fly','Tick'}
{6,8}
{'6','8'}