`r_pick(C;S;I)`

Returns the value of the column at the specified index within a given set of columns.

Function type

Vector only

Syntax

r_pick(C;S;I)

Input

Argument Type Description

Argument	Type	Description
`C`	any	A space- or comma-separated list of column names `C` may also be a string expression (in single quotes) constituting a pattern for matching columns. For instance, `'foo*'` specifies all columns that begin with "foo". If `C` is omitted, the values in all of the columns are included. Note: The columns specified by `C` must be either all numeric (integer and decimal) or all text.
`S`	integer	A boolean column or an expression in `rcv_`/`rcn_`/`rct_` which determines whether or not that column is selected to be included in the calculation. See System variables for more information about `rcv_`/`rcn_`/`rct_`. If `S` is omitted, all columns will be considered by the function (subject to any prior column selections).
`I`	any	A scalar value or the name of a column If `I` is omitted, an error is returned.

C

any

A space- or comma-separated list of column names

C may also be a string expression (in single quotes) constituting a pattern for matching columns. For instance, 'foo*' specifies all columns that begin with "foo".

If C is omitted, the values in all of the columns are included.

Note: The columns specified by C must be either all numeric (integer and decimal) or all text.

S

integer

A boolean column or an expression in rcv_/rcn_/rct_ which determines whether or not that column is selected to be included in the calculation. See System variables for more information about rcv_/rcn_/rct_.

If S is omitted, all columns will be considered by the function (subject to any prior column selections).

I

any

A scalar value or the name of a column

If I is omitted, an error is returned.

Return Value

For each row of the table, r_pick returns the value of the column at index I within the group of columns specified by C.

If I does not match the type of the columns specified by C (i.e., numeric or text), an error is returned.

If there is no match, the result is N/A.

Sample Usage


`c1`	`c2`	`c3`	`c4`	`r_pick(;;2)`	`r_pick(c1 c3;;2)`	`r_pick(c2 c3 c4;;c1)`
2	5	7	2	5	7	7
7	7	4	1	7	4	NA
NA	0	9	3	0	9	NA
NA	NA	NA	NA	NA	NA	NA

Example

<base table="pub.demo.weather.hourly90"/>
<willbe name="b1" value="hour"/>
<willbe name="b2" value="date"/>
<willbe name="b3" value="id"/>
<willbe name="rand" value="draw(12131;0)"/>
<willbe name="ind" value="if(rand<.3;1;rand<.6;2;3)"/>
<willbe name="pick" value="r_pick('b*';;ind)"/>
<willbe name="pick2" value="r_pick(b1 b2 b3;;ind)"/>
<colord cols="b1,b2,b3,rand,ind,pick,pick2"/>