Control contents of an array sample
I have a collection of books. In my view I want to show a random sample of 5 books from the top 10 bestselling books in my DB. However, I only want a maximum of ONE non-fiction title (book.genre) showing in that sample. It's ok if no non-fiction books are sampled.
Controller:
def index
@top_selling_books = Book.all.order('units_sold DESC').first(10).sample(5)
end
View:
<% @top_selling_books.each.with_index(1) do |book, index| %>
<div>
<%= render "books/top_sellers", book: book, index: index %>
</div>
<% end %>
ruby-on-rails ruby
asked Nov 14 '18 at 17:28
B BB B
246138
add a comment |
I have a collection of books. In my view I want to show a random sample of 5 books from the top 10 bestselling books in my DB. However, I only want a maximum of ONE non-fiction title (book.genre) showing in that sample. It's ok if no non-fiction books are sampled.
Controller:
def index
@top_selling_books = Book.all.order('units_sold DESC').first(10).sample(5)
end
View:
<% @top_selling_books.each.with_index(1) do |book, index| %>
<div>
<%= render "books/top_sellers", book: book, index: index %>
</div>
<% end %>
ruby-on-rails ruby
asked Nov 14 '18 at 17:28
B BB B
246138
1
What happens if 7 of the top 10 books are non-fiction? Also to satisfy this requirement you are not truly sampling and should probably partition the dataset
– engineersmnky
Nov 14 '18 at 17:40
1
These requirements don't really make sense for the above mentioned edge case. I would suggest changing them to something like: "Show one of the top 3 non-fiction books, and 4 of the top 10 fiction books". Or maybe some other variation like: "Show one the top 10 overall books that's non-fiction (if it exists), and 4-5 of the top 10 fiction books (but not necessarily top 10 overall books), depending on whether that first book was found"
– Tom Lord
Nov 14 '18 at 17:55
1
...In which case, you could just perform two queries and merge the result. Nothing too fancy.
– Tom Lord
Nov 14 '18 at 17:56
add a comment |
I have a collection of books. In my view I want to show a random sample of 5 books from the top 10 bestselling books in my DB. However, I only want a maximum of ONE non-fiction title (book.genre) showing in that sample. It's ok if no non-fiction books are sampled.
Controller:
def index
@top_selling_books = Book.all.order('units_sold DESC').first(10).sample(5)
end
View:
<% @top_selling_books.each.with_index(1) do |book, index| %>
<div>
<%= render "books/top_sellers", book: book, index: index %>
</div>
<% end %>
ruby-on-rails ruby
asked Nov 14 '18 at 17:28
B BB B
246138
I have a collection of books. In my view I want to show a random sample of 5 books from the top 10 bestselling books in my DB. However, I only want a maximum of ONE non-fiction title (book.genre) showing in that sample. It's ok if no non-fiction books are sampled.
Controller:
def index
@top_selling_books = Book.all.order('units_sold DESC').first(10).sample(5)
end
View:
<% @top_selling_books.each.with_index(1) do |book, index| %>
<div>
<%= render "books/top_sellers", book: book, index: index %>
</div>
<% end %>
ruby-on-rails ruby
ruby-on-rails ruby
asked Nov 14 '18 at 17:28
B BB B
246138
asked Nov 14 '18 at 17:28
B BB B
246138
asked Nov 14 '18 at 17:28
B BB B
246138
asked Nov 14 '18 at 17:28
B BB B
246138
asked Nov 14 '18 at 17:28
B BB B
246138
246138
1
What happens if 7 of the top 10 books are non-fiction? Also to satisfy this requirement you are not truly sampling and should probably partition the dataset
– engineersmnky
Nov 14 '18 at 17:40
1
These requirements don't really make sense for the above mentioned edge case. I would suggest changing them to something like: "Show one of the top 3 non-fiction books, and 4 of the top 10 fiction books". Or maybe some other variation like: "Show one the top 10 overall books that's non-fiction (if it exists), and 4-5 of the top 10 fiction books (but not necessarily top 10 overall books), depending on whether that first book was found"
– Tom Lord
Nov 14 '18 at 17:55
1
...In which case, you could just perform two queries and merge the result. Nothing too fancy.
– Tom Lord
Nov 14 '18 at 17:56
add a comment |
1
What happens if 7 of the top 10 books are non-fiction? Also to satisfy this requirement you are not truly sampling and should probably partition the dataset
– engineersmnky
Nov 14 '18 at 17:40
1
These requirements don't really make sense for the above mentioned edge case. I would suggest changing them to something like: "Show one of the top 3 non-fiction books, and 4 of the top 10 fiction books". Or maybe some other variation like: "Show one the top 10 overall books that's non-fiction (if it exists), and 4-5 of the top 10 fiction books (but not necessarily top 10 overall books), depending on whether that first book was found"
– Tom Lord
Nov 14 '18 at 17:55
1
...In which case, you could just perform two queries and merge the result. Nothing too fancy.
– Tom Lord
Nov 14 '18 at 17:56
1
1
What happens if 7 of the top 10 books are non-fiction? Also to satisfy this requirement you are not truly sampling and should probably partition the dataset
– engineersmnky
Nov 14 '18 at 17:40
What happens if 7 of the top 10 books are non-fiction? Also to satisfy this requirement you are not truly sampling and should probably partition the dataset
– engineersmnky
Nov 14 '18 at 17:40
1
1
These requirements don't really make sense for the above mentioned edge case. I would suggest changing them to something like: "Show one of the top 3 non-fiction books, and 4 of the top 10 fiction books". Or maybe some other variation like: "Show one the top 10 overall books that's non-fiction (if it exists), and 4-5 of the top 10 fiction books (but not necessarily top 10 overall books), depending on whether that first book was found"
– Tom Lord
Nov 14 '18 at 17:55
These requirements don't really make sense for the above mentioned edge case. I would suggest changing them to something like: "Show one of the top 3 non-fiction books, and 4 of the top 10 fiction books". Or maybe some other variation like: "Show one the top 10 overall books that's non-fiction (if it exists), and 4-5 of the top 10 fiction books (but not necessarily top 10 overall books), depending on whether that first book was found"
– Tom Lord
Nov 14 '18 at 17:55
1
1
...In which case, you could just perform two queries and merge the result. Nothing too fancy.
– Tom Lord
Nov 14 '18 at 17:56
...In which case, you could just perform two queries and merge the result. Nothing too fancy.
– Tom Lord
Nov 14 '18 at 17:56
add a comment |
1 Answer
1
active
oldest
votes
If you want to do complicated results, sometimes it's best not to do it all in one query. It can be much harder to maintain than simple logic. However, there is definitely a balance to maintainability, scalability, and performance.
I would suggest doing something like this:
def top_books(limited_genres: )
non_limited_books = Book.where.not(genre: limited_genres).order('units_sold DESC').first(10).sample(5)
limited_books = Book.where(genre: limited_genres).order('units_sold DESC').first(5).sample(1) # rename to limited_book if sample is kept to 1
(top_books + limited_books).sort_by(:units_sold)[0..5]
end
@top_selling_books = top_books(limited_genres: ['non-fiction'])
This is non tested code. It's just to give you an idea on how to accomplish your goals.
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
add a comment |
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1 Answer
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1 Answer
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active
oldest
votes
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oldest
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oldest
votes
If you want to do complicated results, sometimes it's best not to do it all in one query. It can be much harder to maintain than simple logic. However, there is definitely a balance to maintainability, scalability, and performance.
I would suggest doing something like this:
def top_books(limited_genres: )
non_limited_books = Book.where.not(genre: limited_genres).order('units_sold DESC').first(10).sample(5)
limited_books = Book.where(genre: limited_genres).order('units_sold DESC').first(5).sample(1) # rename to limited_book if sample is kept to 1
(top_books + limited_books).sort_by(:units_sold)[0..5]
end
@top_selling_books = top_books(limited_genres: ['non-fiction'])
This is non tested code. It's just to give you an idea on how to accomplish your goals.
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
add a comment |
If you want to do complicated results, sometimes it's best not to do it all in one query. It can be much harder to maintain than simple logic. However, there is definitely a balance to maintainability, scalability, and performance.
I would suggest doing something like this:
def top_books(limited_genres: )
non_limited_books = Book.where.not(genre: limited_genres).order('units_sold DESC').first(10).sample(5)
limited_books = Book.where(genre: limited_genres).order('units_sold DESC').first(5).sample(1) # rename to limited_book if sample is kept to 1
(top_books + limited_books).sort_by(:units_sold)[0..5]
end
@top_selling_books = top_books(limited_genres: ['non-fiction'])
This is non tested code. It's just to give you an idea on how to accomplish your goals.
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
add a comment |
If you want to do complicated results, sometimes it's best not to do it all in one query. It can be much harder to maintain than simple logic. However, there is definitely a balance to maintainability, scalability, and performance.
I would suggest doing something like this:
def top_books(limited_genres: )
non_limited_books = Book.where.not(genre: limited_genres).order('units_sold DESC').first(10).sample(5)
limited_books = Book.where(genre: limited_genres).order('units_sold DESC').first(5).sample(1) # rename to limited_book if sample is kept to 1
(top_books + limited_books).sort_by(:units_sold)[0..5]
end
@top_selling_books = top_books(limited_genres: ['non-fiction'])
This is non tested code. It's just to give you an idea on how to accomplish your goals.
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
If you want to do complicated results, sometimes it's best not to do it all in one query. It can be much harder to maintain than simple logic. However, there is definitely a balance to maintainability, scalability, and performance.
I would suggest doing something like this:
def top_books(limited_genres: )
non_limited_books = Book.where.not(genre: limited_genres).order('units_sold DESC').first(10).sample(5)
limited_books = Book.where(genre: limited_genres).order('units_sold DESC').first(5).sample(1) # rename to limited_book if sample is kept to 1
(top_books + limited_books).sort_by(:units_sold)[0..5]
end
@top_selling_books = top_books(limited_genres: ['non-fiction'])
This is non tested code. It's just to give you an idea on how to accomplish your goals.
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
answered Nov 14 '18 at 18:54
DbzDbz
2,00142743
2,00142743
add a comment |
add a comment |
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1
What happens if 7 of the top 10 books are non-fiction? Also to satisfy this requirement you are not truly sampling and should probably partition the dataset
– engineersmnky
Nov 14 '18 at 17:40
1
These requirements don't really make sense for the above mentioned edge case. I would suggest changing them to something like: "Show one of the top 3 non-fiction books, and 4 of the top 10 fiction books". Or maybe some other variation like: "Show one the top 10 overall books that's non-fiction (if it exists), and 4-5 of the top 10 fiction books (but not necessarily top 10 overall books), depending on whether that first book was found"
– Tom Lord
Nov 14 '18 at 17:55
1
...In which case, you could just perform two queries and merge the result. Nothing too fancy.
– Tom Lord
Nov 14 '18 at 17:56