Adding map and/or reject to a reduce in rails view
I am calculating an ROI value that averages over a category.
<% @categories.each do |category| %>
<h3><strong><%= category.name %><strong></h3>
<% @category_products = category.products_by_warehouse_id(params[:id]) %>
<!-- add map/reject below -->
<%@ROI = (@category_products.reduce(0.0) {|acc, item| acc + (item.heritable_sale_price.to_f * item.product_selections.length) / item.purchase_price.to_f }) %>
<p> Category ROI: <%= number_with_precision((@ROI / @category_products.length.to_f), precision:2) %></p>
.....(close tags)......
The value throws NaN when financial data is missing. For individual values, this is fine; however, it does the same for averages with missing data as well.
How can I add map/reject into my call to throw out nil values, and get the average of what's available?
@category_products.length.to_f would also have to skip over empty elements in the array if I go this route as well, to keep the sum and length consistent. Something like .where(purchase_price: [!nil, ""]).size may work.
ruby-on-rails ruby oop view
edited Nov 26 '18 at 8:56
sawa
132k29206306
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
add a comment |
I am calculating an ROI value that averages over a category.
<% @categories.each do |category| %>
<h3><strong><%= category.name %><strong></h3>
<% @category_products = category.products_by_warehouse_id(params[:id]) %>
<!-- add map/reject below -->
<%@ROI = (@category_products.reduce(0.0) {|acc, item| acc + (item.heritable_sale_price.to_f * item.product_selections.length) / item.purchase_price.to_f }) %>
<p> Category ROI: <%= number_with_precision((@ROI / @category_products.length.to_f), precision:2) %></p>
.....(close tags)......
The value throws NaN when financial data is missing. For individual values, this is fine; however, it does the same for averages with missing data as well.
How can I add map/reject into my call to throw out nil values, and get the average of what's available?
@category_products.length.to_f would also have to skip over empty elements in the array if I go this route as well, to keep the sum and length consistent. Something like .where(purchase_price: [!nil, ""]).size may work.
ruby-on-rails ruby oop view
edited Nov 26 '18 at 8:56
sawa
132k29206306
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
1
You can try using where.not to query your category_products:where.not(heritable_sale_price: nil, product_selections: nil, purchase_price: nil). If that doesn't fix your problem, any second method called within the reduce block on the item variable is able to throw a NoMethodError.
– Sebastian Palma
Nov 26 '18 at 2:09
If I take :purchase_price alone (:product_selections is a joined class, and sale price is a method) this works, and set up a second instance of <%@category_products_count = category.products_by_warehouse_id(params[:id]).where.not(purchase_price: nil).size%>in order to have consistent values for averaging. Submit as an answer?
– Boucherie
Nov 26 '18 at 18:11
add a comment |
I am calculating an ROI value that averages over a category.
<% @categories.each do |category| %>
<h3><strong><%= category.name %><strong></h3>
<% @category_products = category.products_by_warehouse_id(params[:id]) %>
<!-- add map/reject below -->
<%@ROI = (@category_products.reduce(0.0) {|acc, item| acc + (item.heritable_sale_price.to_f * item.product_selections.length) / item.purchase_price.to_f }) %>
<p> Category ROI: <%= number_with_precision((@ROI / @category_products.length.to_f), precision:2) %></p>
.....(close tags)......
The value throws NaN when financial data is missing. For individual values, this is fine; however, it does the same for averages with missing data as well.
How can I add map/reject into my call to throw out nil values, and get the average of what's available?
@category_products.length.to_f would also have to skip over empty elements in the array if I go this route as well, to keep the sum and length consistent. Something like .where(purchase_price: [!nil, ""]).size may work.
ruby-on-rails ruby oop view
edited Nov 26 '18 at 8:56
sawa
132k29206306
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
I am calculating an ROI value that averages over a category.
<% @categories.each do |category| %>
<h3><strong><%= category.name %><strong></h3>
<% @category_products = category.products_by_warehouse_id(params[:id]) %>
<!-- add map/reject below -->
<%@ROI = (@category_products.reduce(0.0) {|acc, item| acc + (item.heritable_sale_price.to_f * item.product_selections.length) / item.purchase_price.to_f }) %>
<p> Category ROI: <%= number_with_precision((@ROI / @category_products.length.to_f), precision:2) %></p>
.....(close tags)......
The value throws NaN when financial data is missing. For individual values, this is fine; however, it does the same for averages with missing data as well.
How can I add map/reject into my call to throw out nil values, and get the average of what's available?
@category_products.length.to_f would also have to skip over empty elements in the array if I go this route as well, to keep the sum and length consistent. Something like .where(purchase_price: [!nil, ""]).size may work.
ruby-on-rails ruby oop view
ruby-on-rails ruby oop view
edited Nov 26 '18 at 8:56
sawa
132k29206306
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
edited Nov 26 '18 at 8:56
sawa
132k29206306
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
edited Nov 26 '18 at 8:56
sawa
132k29206306
edited Nov 26 '18 at 8:56
sawa
132k29206306
edited Nov 26 '18 at 8:56
sawa
132k29206306
132k29206306
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
asked Nov 26 '18 at 1:47
BoucherieBoucherie
315213
315213
1
You can try using where.not to query your category_products:where.not(heritable_sale_price: nil, product_selections: nil, purchase_price: nil). If that doesn't fix your problem, any second method called within the reduce block on the item variable is able to throw a NoMethodError.
– Sebastian Palma
Nov 26 '18 at 2:09
If I take :purchase_price alone (:product_selections is a joined class, and sale price is a method) this works, and set up a second instance of <%@category_products_count = category.products_by_warehouse_id(params[:id]).where.not(purchase_price: nil).size%>in order to have consistent values for averaging. Submit as an answer?
– Boucherie
Nov 26 '18 at 18:11
add a comment |
1
You can try using where.not to query your category_products:where.not(heritable_sale_price: nil, product_selections: nil, purchase_price: nil). If that doesn't fix your problem, any second method called within the reduce block on the item variable is able to throw a NoMethodError.
– Sebastian Palma
Nov 26 '18 at 2:09
If I take :purchase_price alone (:product_selections is a joined class, and sale price is a method) this works, and set up a second instance of <%@category_products_count = category.products_by_warehouse_id(params[:id]).where.not(purchase_price: nil).size%>in order to have consistent values for averaging. Submit as an answer?
– Boucherie
Nov 26 '18 at 18:11
1
1
You can try using where.not to query your category_products:
where.not(heritable_sale_price: nil, product_selections: nil, purchase_price: nil). If that doesn't fix your problem, any second method called within the reduce block on the item variable is able to throw a NoMethodError.– Sebastian Palma
Nov 26 '18 at 2:09
You can try using where.not to query your category_products:
where.not(heritable_sale_price: nil, product_selections: nil, purchase_price: nil). If that doesn't fix your problem, any second method called within the reduce block on the item variable is able to throw a NoMethodError.– Sebastian Palma
Nov 26 '18 at 2:09
If I take :purchase_price alone (:product_selections is a joined class, and sale price is a method) this works, and set up a second instance of <%
@category_products_count = category.products_by_warehouse_id(params[:id]).where.not(purchase_price: nil).size%> in order to have consistent values for averaging. Submit as an answer?– Boucherie
Nov 26 '18 at 18:11
If I take :purchase_price alone (:product_selections is a joined class, and sale price is a method) this works, and set up a second instance of <%
@category_products_count = category.products_by_warehouse_id(params[:id]).where.not(purchase_price: nil).size%> in order to have consistent values for averaging. Submit as an answer?– Boucherie
Nov 26 '18 at 18:11
add a comment |
1 Answer
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So, in order to make sure, that none of the methods being accessed within the reduce block, to the item object are going to return nil, which hence, would throw a NoMethodError, you could firstly check them at the moment of creating your query. A where.not would do that. But keeping in mind that it'll leave aside each record in the database which doesn't satisfy the query criteria.
For that, then:
where.not(
heritable_sale_price: nil,
product_selections: nil,
purchase_price: nil
)
For that, you can analyze the option on setting a default value for each of those columns, so this helps you avoiding the previous query, and having to rescue on each case where there's no value for them. You can see the Rails Migration docs.
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
add a comment |
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So, in order to make sure, that none of the methods being accessed within the reduce block, to the item object are going to return nil, which hence, would throw a NoMethodError, you could firstly check them at the moment of creating your query. A where.not would do that. But keeping in mind that it'll leave aside each record in the database which doesn't satisfy the query criteria.
For that, then:
where.not(
heritable_sale_price: nil,
product_selections: nil,
purchase_price: nil
)
For that, you can analyze the option on setting a default value for each of those columns, so this helps you avoiding the previous query, and having to rescue on each case where there's no value for them. You can see the Rails Migration docs.
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
add a comment |
So, in order to make sure, that none of the methods being accessed within the reduce block, to the item object are going to return nil, which hence, would throw a NoMethodError, you could firstly check them at the moment of creating your query. A where.not would do that. But keeping in mind that it'll leave aside each record in the database which doesn't satisfy the query criteria.
For that, then:
where.not(
heritable_sale_price: nil,
product_selections: nil,
purchase_price: nil
)
For that, you can analyze the option on setting a default value for each of those columns, so this helps you avoiding the previous query, and having to rescue on each case where there's no value for them. You can see the Rails Migration docs.
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
add a comment |
So, in order to make sure, that none of the methods being accessed within the reduce block, to the item object are going to return nil, which hence, would throw a NoMethodError, you could firstly check them at the moment of creating your query. A where.not would do that. But keeping in mind that it'll leave aside each record in the database which doesn't satisfy the query criteria.
For that, then:
where.not(
heritable_sale_price: nil,
product_selections: nil,
purchase_price: nil
)
For that, you can analyze the option on setting a default value for each of those columns, so this helps you avoiding the previous query, and having to rescue on each case where there's no value for them. You can see the Rails Migration docs.
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
So, in order to make sure, that none of the methods being accessed within the reduce block, to the item object are going to return nil, which hence, would throw a NoMethodError, you could firstly check them at the moment of creating your query. A where.not would do that. But keeping in mind that it'll leave aside each record in the database which doesn't satisfy the query criteria.
For that, then:
where.not(
heritable_sale_price: nil,
product_selections: nil,
purchase_price: nil
)
For that, you can analyze the option on setting a default value for each of those columns, so this helps you avoiding the previous query, and having to rescue on each case where there's no value for them. You can see the Rails Migration docs.
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
answered Nov 27 '18 at 10:21
Sebastian PalmaSebastian Palma
16.1k42135
16.1k42135
add a comment |
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You can try using where.not to query your category_products:
where.not(heritable_sale_price: nil, product_selections: nil, purchase_price: nil). If that doesn't fix your problem, any second method called within the reduce block on the item variable is able to throw a NoMethodError.– Sebastian Palma
Nov 26 '18 at 2:09
If I take :purchase_price alone (:product_selections is a joined class, and sale price is a method) this works, and set up a second instance of <%
@category_products_count = category.products_by_warehouse_id(params[:id]).where.not(purchase_price: nil).size%>in order to have consistent values for averaging. Submit as an answer?– Boucherie
Nov 26 '18 at 18:11