[Help] - Using unary operators with multiple inputs

[praveentiru]

I prefer to use Dataframe API directly and I am trying to do the same. I am new to library so, I am unable to figure out how to use certain functions in logical_plan that are declared as unary operators but actually need multiple inputs.

Examples:

• concat - I am assuming should take multiple columns as input and concat them
• regexp_match - Physical plan refers 3 arguments, column being operated on, regex, options
• split_part - This function need 3 inputs, column being split, delimiter, index of text to take

Common signature in all 3 cases is: pub fn function_name(e: Expr) -> Expr

Question: How does proper input expression for this to work?

[praveentiru]

It seems that this is lack of proper implementation for certain functions. After upgrading the dependency from "4.0" to "5.0" the signature of concat has changed from pub fn concat(e: Expr) -> Expr to pub fn concat(args: &[Expr]) -> Expr.

It would be helpful to new users to documents functions that are yet to be properly implemented. I will try to create a list but, need someone to validate this properly.