Retrieves the substring from a column expression related to a variable component.
Usage
h_colexpr_substr(var, col_expr)
Arguments
- var
Variable to extract from the expression.
- col_expr
Column expression string.
Value
Substring corresponding to the variable.
Details
get substring from col_expr related to var component
intended usage is on strings coming from .spl_context$cur_col_expr
these strings are of type '!(is.na(var) & var