I would like to know if you have any more practical way of working with keys, value in ruby.
I had to improvise to be able to access and print the keys Rafael and Roberto and at the same time print their keys and values
My code:
arr = Hash.new
arr["Rafael"] = []
arr["Roberto"] = []
listaProdutos = [
"banana",
"uva",
"biscoito"
]
listaProdutos.each{ |i|
arr["Rafael"] << {"Produto": i, "Quantidade": rand(1..9)}
arr["Roberto"] << {"Produto": i, "Quantidade": rand(1..9)}
}
arr.each{ |k,lista|
(0..arr.count).each do |i|
puts "#{k} vai comprar #{arr[k][i][:Quantidade]} unidades de #{arr[k][i][:Produto]}"
end
}
This:
arr.each{ |k,lista|
(0..arr.count).each do |i|
puts "#{k} vai comprar #{arr[k][i][:Quantidade]} unidades de #{arr[k][i][:Produto]}"
end
}
Can we rewritten as:
arr.each do |k, lista|
lista.each do |obj|
puts "#{k} vai comprar #{obj[:Quantidade]} unidades de #{obj[:Produto]}"
end
end
Related
I have the following code:
#model = "ford"
#attribute = "name"
def grouped
grouped = {}
#array.each do |r|
field = r.car.send(#model)
if field.is_a? ActiveRecord::Associations::CollectionProxy
field.each do |obj|
key = obj.send(#attribute)
grouped[key] = [] unless grouped.has_key?(key)
grouped[key].push(r)
end
else
key = field.send(#attribute)
grouped[key] = [] unless grouped.has_key?(key)
grouped[key].push(r)
end
end
grouped
end
The result is:
{ford: [a, b, c]}
The codeclimate says that it has cognitive complexity.
How can I refactor this method to something cleaner?
def grouped
#array.each_with_object(Hash.new { |h, k| h[k] = [] }) do |r, grouped|
case field = r.car.send(#model)
when ActiveRecord::Associations::CollectionProxy
field.each do |obj|
grouped[obj.send(#attribute)] << r
end
else
grouped[field.send(#attribute)] << r
end
end
end
I have an Array-1 say
arr1 =['s','a','sd','few','asdw','a','sdfeg']
And a second Array
arr2 = ['s','a','d','f','w']
I want to take arr1 and sort the frequency of letters by inputting arr2 with result
[s=> 4, a=> 2, d => 3] So on and so forth.
As far as I can muddle around.. Nothing below works, Just my thoughts on it?
hashy = Hash.new
print "give me a sentance "
sentance = gets.chomp.downcase.delete!(' ')
bing = sentance.split(//)
#how = sentance.gsub!(/[^a-z)]/, "") #Remove nil result
#chop = how.to_s.split(//).uniq
#hashy << bing.each{|e| how[e] }
#puts how.any? {|e| bing.count(e)}
#puts how, chop
bing.each {|v| hashy.store(v, hashy[v]+1 )}
puts bing
Thank you for your time.
I assumed that you want to count all letters in the sentence you put in, and not array 1. Assuming that, here's my take on it:
hashy = Hash.new()
['s','a','d','f','w'].each {|item| hashy[item.to_sym] = 0}
puts "give me a sentence"
sentence = gets.chomp.downcase.delete!(' ')
sentence_array = []
sentence.each_char do |l|
sentence_array.push(l)
end
hashy.each do |key, value|
puts "this is key: #{key} and value #{hashy[key]}"
sentence_array.each do |letter|
puts "letter: #{letter}"
if letter.to_sym == key
puts "letter #{letter} equals key #{key}"
value = value + 1
hashy[key] = value
puts "value is now #{value}"
end
end
end
puts hashy
a beginner question here, please help me out
my_array = ["city1:state1","city2:state2","city3:state1","city4:state3","city5:state1"]
from this array how can i make a hash like this?
{
state1: [city1,city3,city5],
state2: [city2],
state3: [city4]
}
i am trying this way
my_hash = { }
my_array.each do |cs|
temp = cs.split(":")
if my_hash.keys.include? temp[1]
my_hash[temp[1]] = temp[0]
else
my_hash[temp[1]] = temp[0]
end
end
but i am not getting how to match keys of my hash and append to keys.
A little modification can work:
my_hash = { }
my_array.each do |cs|
temp = cs.split(":")
if my_hash.keys.include? temp[1].to_sym
my_hash[temp[1].to_sym] << temp[0]
else
my_hash[temp[1].to_sym] = [temp[0]]
end
end
Result is {:state1=>["city1", "city3", "city5"], :state2=>["city2"], :state3=>["city4"]}. I'm assuming this is what you mean (the keys are symbols, and the values are arrays of strings).
You can use Hash defaults to achieve an alternative solution:
my_array = ["city1:state1","city2:state2","city3:state1","city4:state3","city5:state1"]
hash = Hash.new do |hash, key|
hash[key] = []
end
my_array.each_with_object(hash) do |string, hash|
city, state = string.split(":")
hash[state.to_sym] << city
end
# => {:state1=>["city1", "city3", "city5"], :state2=>["city2"], :state3=>["city4"]}
Try this(considering that you mistyped state3:[city3] instead of state3:[city4] in your question):
my_array = ["city1:state1","city2:state2","city3:state1","city4:state3","city5:state1"]
my_hash = { }
my_array.each do |cs|
value, key = cs.split(":")
key = key.to_sym
if my_hash[key].present?
my_hash[key] << value
else
my_hash[key] = [value]
end
end
my_hash #=> {:state1=>["city1", "city3", "city5"], :state2=>["city2"], :state3=>["city4"]}
Or, one-liner:
my_hash = my_array.inject({}){|h, cs| value, key = cs.split(":"); key = key.to_sym; h[key].present? ? (h[key] << value) : h[key] = [value]; h }
my_hash #=> {:state1=>["city1", "city3", "city5"], :state2=>["city2"], :state3=>["city4"]}
or even better(based on jesper's idea of Hash):
my_array.inject(Hash.new{|h,k| h[k] = [] }){ |my_hash, cs| value, key = cs.split(":"); my_hash[key.to_sym] << value; my_hash }
my_hash #=> {:state1=>["city1", "city3", "city5"], :state2=>["city2"], :state3=>["city4"]}
How can I have a hash of hash of hash?
My test returns
undefined method `[]' for nil:NilClass (NoMethodError)
Any tips?
found = Hash.new()
x = 1;
while x < 4 do
found[x] = Hash.new()
y = 1
while y < 4 do
found[x][y] = Hash.new()
found[x][y]['name1'] = 'abc1'
found[x][y]['name2'] = 'abc2'
found[x][y]['name3'] = 'abc3'
y += 1
end
x += 1
end
found.each do |k, v, y|
puts "k : #{k}"
puts " : #{v[y['name1']]}"
puts " : #{v[y['name2']]}"
puts " : #{v[y['name3']]}"
puts
end
I think you want something like this:
First of all create the data structure. You want nested hashes so you need to define default values for each hash key.
found = Hash.new do |hash,key|
hash[key] = Hash.new do |hash,key|
hash[key] = Hash.new
end
end
Run the search
(1..3).each do |x|
(1..3).each do |y|
found[x][y]['name1'] = 'abc1'
found[x][y]['name2'] = 'abc1'
found[x][y]['name3'] = 'abc1'
end
end
Then display the results
found.each do |x, y_hash|
y_hash.each do |y, name_hash|
name_hash.each do |name, value|
puts "#{x} => #{y} => #{name} => #{value}"
end
end
end
The way you build the hash seems to be functional. What probably causes the error is this loop:
found.each do |k, v, y|
Hash#each yields key/value pairs, so y will be assigned nil, thus causing the error two lines below. What you probably meant is a nested loop like
found.each do |x, h1|
h1.each do |y, h2|
puts h2['name1']
end
end
You should also be aware that you can write these kinds of counting loops more concisely in Ruby:
found = Hash.new { |h,k| h[k] = {} }
1.upto(3) do |x|
1.upto(3) do |y|
found[x][y] = {
'name1' => 'abc1',
'name2' => 'abc2',
'name3' => 'abc3',
}
end
end
I'm probably trying to be hard headed about this. I'm trying to format hash key and and array of values for output to user. Ruby-doc give me the code for it for one value. http://www.ruby-doc.org/core/classes/Hash.html#M002861
h = { "a" => 100, "b" => 200 }
h.each {|key, value| puts "#{key} is #{value}" }
I'm trying to get
h = { "a" => [100,'green'], "b" => [200,'red'] }
h.each {|key, m,n| puts "#{key} is #{m} and #{n}"}
produces:
a is 100 and green
b is 200 and red
I've had some luck with
h.each{|key,m,n| puts "#{key} is #{[m,'n']} "}
it produces:
a is 100green
b is 200red
I need some space between my array of elements, how do I go about doing that?
h.each {|key, (m, n)| puts "#{key} is #{m} and #{n}"}
h.each { |key, value| puts "#{key} is #{value.first} and #{value.last}" }
I'm a fan of each_pair for hashes:
h.each_pair {|key, val| puts "#{key} is #{val[0]} and #{val[1]}" }
Or
h.each_pair {|key, val| puts "#{key} is #{val.join(' and ')}"}
h.each {|k,v| puts "#{k} is #{v[0]} and #{v[1]}"}