`r_mapstring(C;S;X;D)`

Returns a string consisting of a list of elements, each of which is the result of evaluating an expression on the current column, concatenated together using the specified delimiter.

Function type

Vector only

Syntax

r_mapstring(C;S;X;D)

Input

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).
`X`	any	A column name `X` is an expression that is used to transform the value or name of each of the selected columns. Note: Use the system variables `rcv_` and `rcn_` to reference the column value and name, respectively.
`D`	text	A scalar value or the name of a column The character to be used as the delimiter in the resultant string. If `D` is omitted, no delimiter is used.

Return Value

For each row of the table, r_mapstring returns a text value that consists of a list of elements delimited by D. The list of elements is comprised of the value or name of each selected column (as specified by C and S) transformed using the expression defined by X. If X is omitted, then the values are simply the values of each column (or rcv_, the default). If C is a matching expression that matches no columns, or if S is false for all matching columns at a particular row, r_mapstring returns an empty string.