I have included given code
#marks= Mark.all
which gives me this
#<ActiveRecord::Relation [#<Mark id: 1, name: "xyz", number: 20>, #<Mark id: 2, name: "abc", number: 25>, #<Mark id: 3, name: "toy", number: 40>, #<Mark id: 4, name: "tim", number: 35>, #<Mark id: 5, name: "vim", number: 45>]>
Now I want to make a new hash of marks i.e {1=>"xyz", 2=>"abc", 3=>"toy", 4=>"tim", 5=>"vim"}. Please guide me how to obtain this thanks in advance.
try this
#marks = Mark.all
#hashed_marks = Hash[#marks.collect{|v| [ v.id, v.name ] }]
#marks = Mark.all
#hashed_marks = Hash[#marks.pluck(:id, :name)]
You can do
#marks = Mark.all
marks_hash = {}
#marks.each do |mark|
marks_hash.merge( mark.attributes )
end
marks_hash
Another way you can do it is:
#marks.as_json
If you change your marks code to use pluck
#marks = Mark.pluck(:id, :name)
You will then just get a multi dimensional array
[[1, "xyz"], [2, "abc"]]
Then you can just do
#hash = Hash[#marks] => {1=>"xyz", 2=>"abc"}
Try this:
my_hash = Hash.new
Mark.all.each{|m| my_hash[m.id] = m.name }
Or
If you are using Rails 4 then use pluck and to_h
my_hash = Mark.pluck(:id, :name).to_h
Related
I have an array and it has many columns and I want to change one value of my one column.
My array is:
[
{
id: 1,
Districts: "Lakhisarai",
Area: 15.87,
Production: 67.77,
Productivity: 4271,
Year: 2015,
Area_Colour: "Red",
Production_Colour: "Orange",
Productivity_Colour: "Dark_Green",
created_at: "2018-07-24T11:24:13.000Z",
updated_at: "2018-07-24T11:24:13.000Z"
},
{
id: 29,
Districts: "Begusarai",
Area: 18.53,
Production: 29.35,
Productivity: 1584,
Year: 2015,
Area_Colour: "Red",
Production_Colour: "Red",
Productivity_Colour: "Orange",
created_at: "2018-07-24T11:24:13.000Z",
updated_at: "2018-07-24T11:24:13.000Z"
},
...
]
This is my sample array and I want my Productivity to be divided by 100 for that I am using one empty array and pushing these hashes to my array like:
j = []
b.map do |k|
if k.Productivity
u = k.Productivity/100
j.push({id: k.id, Productivity: u })
else
j.push({id: k.id, Productivity: k.Productivity })
end
Is there any simple way where I can generate this kind of array and reflect my changes to to one column. Is there any way where I don't need to push name of column one by one in push method.
I want to generate exact same array with one modification in productivity
let's say your array is e, then:
e.each { |item| item[:Productivity] = item[:Productivity]/100}
Example:
e = [{p: 12, d: 13}, {p:14, d:70}]
e.each { |item| item[:p] = item[:p]/10}
output: [{:p=>1, :d=>13}, {:p=>1, :d=>70}]
You could take help of map method here to create a new array from your original array, but with the mentioned changes.
ary.map do |elem|
h = elem.slice(:id)
h[:productivity] = elem[:Productivity] / 100 if elem[:Productivity]
h
end
=> [{:id=>1, :productivity=>42}, {:id=>29, :productivity=>15}]
Note, Hash#slice returns a new hash with only the key-value pairs for the keys passed in argument e.g. here, it returns { id: 1 } for first element.
Also, we are assigning the calculated productivity to the output only when it is set on original hash. Hence, the if condition there.
I am currently working on statistics, so I get an array containing all my data. The problem is that this data contains enums and that I would like to translate them without overwriting the rest.
Here is a given example that contains my array (it contains several hundred) :
#<Infosheet id: 90, date: "2018-04-22 00:00:00", number: 7, way: "home", gender: "man", age: "age1", district: "", intercommunal: "", appointment: true, othertype: "", otherorientation: "", user_id: 3, created_at: "2018-04-22 17:51:16", updated_at: "2018-04-22 17:51:16", typerequest_id: 168, orientation_id: 188, info_number: nil, city_id: 105>
I would like to translate the enums of "way" or "gender" or "age", while retaining the rest of the data, because currently, if I make a translation in the console, it crushes everything else.
Do you know how to make that ?
Thanks !
You can just loop over all the enum attributes and get their values. Later you can merge and pass a new hash containing converted values
ENUM_COLUMNS = %i[way gender age] # Equivalent to [:way, :gender, :age]
def convert_enums
overrided_attributes = {}
ENUM_COLUMNS.each { |column| overrided_attributes[column.to_s] = self[column] }
attributes.merge(overrided_attributes)
end
NOTE:
While infosheet.gender returns you male or female
infosheet[:gender] will return you the respective integer value 0 or 1
You can test this if you use translate enum gem :
a = Infosheet.group(:gender).count
{“male”=>30, “female”=>6532}
Create a hash
r = Hash.new
And populate this with :
a.each {|s| puts r[Infosheet.translated_gender(s[0])]=s[1] }
r
result :
{“homme”=>30, “femme”=>6532}
I have a table Status already seeded. I wanted to get:
['Aberto', 'Pendente', 'Concluido', 'Fechado']
and when I type:
Status.all.to_a.each { |u| u.nome }
I get:
[#<Status id: 1, nome: "Aberto">, #<Status id: 2, nome: "Pendente">, #<Status id: 3, nome: "Concluido">, #<Status id: 4, nome: "Fechado">]
Can anyone tell me what's happening?
Array#each is used for iteration, Array#map is used to for mapping. Here you wanted to map nome to each status. Therefore, just use Array#map:
Status.all.to_a.map { |u| u.nome }
Or even better, the shortcut:
Status.all.to_a.map(&:nome)
You can use pluck
Status.pluck(:nome) # => ['Aberto', 'Pendente', 'Concluido', 'Fechado']
I have a model called coverage that looks like this
1.9.3p429 :005 > Coverage.new
=> #<Coverage id: nil, postcode: nil, name: nil, created_at: nil, updated_at: nil>
Here is an example record:
1.9.3p429 :006 > Coverage.find(10)
Coverage Load (7.3ms) SELECT "coverages".* FROM "coverages" WHERE "coverages"."id" = $1 LIMIT 1 [["id", 10]]
=> #<Coverage id: 10, postcode: "N10", name: "N10 - Muswell Hill", created_at: "2013-05-22 14:42:37", updated_at: "2013-05-22 14:42:37">
I've got over 300 postcodes and I want to group them by some values I have in this array
group = ['N','E','EC','LS','TS']
So I would like to do
#postcodes = Coverage.all
run it through something with the above array to get the following hash
#postcode_hash = { 'N' => [ '#Active Record for N1', '#Active Record for N2' ], 'E' => [ '#Active Record for E1', '#Active Record for E2' ] }
# note: not complete should contain all index from the above array
You can use the .group_by{} method:
#postcodes = Coverage.all
#postcodes_hash = #postcodes.group_by{ |c| c.postcode.gsub(/[0-9]/, '') }
Take a look at the group_by documentation:
http://apidock.com/rails/Enumerable/group_by
There is the explicit version of above:
#postcode_hash = {}
group = ['N','E','EC','LS','TS']
group.each{ |code| #postcode_hash[code] = [] }
#postcodes = Coverage.scoped # similar to .all but better
#postcodes.map do |coverage|
code = coverage.postcode.gsub(/[0-9]/, '') # takes off all the numbers of the postcode
#postcode_hash[code] << coverage if #postcode_hash[code]
end
Ok so I have a sale model that
recent_sales = Sale.recent
=> [#<Sale id: 7788, contact_id: 9988, purchasing_contact_id: 876, event_id: 988, #<BigDecimal:7fdb4ac06fe8,'0.0',9(18)>, fulfilled_at: nil, skip_print: nil, convention_id: 6, refund_fee: #<BigDecimal:7fdb4ac06de0,'0.0',9(18)>, processing: false>, #<Sale id: 886166, , contact_id: 7775,
recent_sales.count
=> 32
I know i can do this
grouped_sales = recent_sales.group_by(&:contact_id).map {|k,v| [k, v.length]}
=> [[9988, 10], [7775, 22]]
But what i really need is not just grouping on contact_id but also event_id so the final results looks like this
=> [[9988, 988, 5], [9988, 977, 5], [7775, 988, 2], [7775, 977, 20]]
so i have the event_id and the grouping is splitting them up correctly...any ideas on how to do this
I tried
recent_sales.group('contact_id, event_id').map {|k,v| [k, k.event, v.length]}
but no go
grouped_sales = recent_sales.group_by { |s| [s.contact_id, s.event_id] }
.map { |k,v| [k.first, k.last, v.length] }
Simply, try
group(['contact_id','event_id'])
It worked for me. So, I posted as answer to help others as well.
Ask the database to do the grouping
grouped_sales = recent_sales.group([:contact_id, :event_id]).count
the result is a hash each key is an array of the contact and event id, and the value is the count.
So if you want arrays of three
grouped_sales = recent_sales.group([:contact_id, :event_id]).count.map{ |k,v| k << v }