reject_row, select_row, etc. methods
lokeshh opened this issue · 5 comments
The following methods will be very useful:
reject_row,select_row: When you want to filter rows given a condition.map_row: To apply a function to every row.
Similarly for columns.
Applying a function on a row when a given condition is satisfied by the row is a commonly encountered thing. How can we deal with it? @zverok
Are you suggesting something like subsequent operations of filter and map? If this functionality isn't already there, it would be good to adopt these names as this is what they are usually known by.
I was wrong. Looked around and a bit and found out that these things already exist in Enumerable and from enumerate.rb it looks like we would need to implement them.
@lokeshh For me, it seems like NMatrix should be fast & minimal in the first place, "fancy" things go to daru, probably.
So, as each_row without block returns decent Enumerator, you always can do matrix.each_row.reject, or matrix.each_column.select. Unfortunately, #550 is currently standing in the way of this usage. Another possible consideration is maybe you want matrix.map_rows to produce NMatrix again, but probably calling .to_nm on the result is probably good enough?..
Have you tried using #inject_rank along with a select or reject?