Prolog - How to Convert CSV File Output Rows into Queryable Terms?

Question

I am trying to learn to use Prolog and was very pleasantly surprised to find SWI Prolog provides a CSV library out of the box: https://www.swi-prolog.org/pldoc/man?section=csv

However I have no idea how to use it, specifically, with below data (saved inside Data.csv file):

Name,Value
A,150
B,300
C,50

And below snippet:

:- use_module(library(csv)).

get_data(Rows) :-
    csv_read_file("Data.csv", Rows).

I could in swipl easily get the following:

> swipl .\Code.pl
1 ?- get_data(Rows).
Rows = [row('Name', 'Value'), row('A', 150), row('B', 300), row('C', 50)].

However, the return result looks like a list of terms, and there are two issues:

1. How do I skip the first header row? I tried to look at documentation and couldn't figure out an easy way. ChatGPT says I might need to use csv_read_stream instead? Can you please show an example?
2. What do I do with Rows? What I would like to do is to interactively make queries in swipl just as with raw prolog terms/predicates loaded as a .pl file. E.g. I wish to issue queries like this: ?- row(Name,Value), Value > 150. to find all names with Value above a certain value.

Thanks!

Remark:

• Import csv file data to populate a Prolog knowledge base Partly answers my question but it says "see it at documentation" which I tried and couldn't comprehend - I need specific code examples on how to ignore the first header row and how to make use of the returned list as queryable knowledge.

Answer 1

To get the tail part of the list, you can pattern match in the query itself.

get_data([Header|Rows]).

Now with the Rows you have, you need to check for members of the list.

?- member(X, [1, 2, 3, 4]), X >= 3.
X = 3 ;
X = 4.

so full query would be something like:

get_data([Header|Rows]), member(row(Name, Value), Rows), Value > 50.