How can I write this conditional in fewer lines? - ruby-on-rails

I wrote this code in my model:
percentage = 0
if self.date_of_birth.present?
percentage += 15
end
if self.gender.present?
percentage += 15
end
if self.relationship_status.present?
percentage += 10
end
if self.language.present?
percentage += 10
end
if self.qualification.present?
percentage += 10
end
if self.interests.present?
if self.interests.count >= 10
percentage += 10
else
percentage += self.interests.count * 5
end
end
But it does not look good. It is a lot of code for a small thing. I want to reduce the number of lines.

You can do it inline, like this:
percentage += 15 if self.date_of_birth.present?
Instead of this:
if self.interests.count >= 10
percentage += 10
else
percentage += self.interests.count*5
end
You can use a ternary operator:
percentage += self.interests.count >= 10 ? 10 : self.interests.count*5

percentage = [
(15 if date_of_birth.present?),
(15 if gender.present?),
(10 if relationship_status.present?),
(10 if language.present?),
(10 if qualification.present?),
((counts = interests.count.to_i) >= 10 ? 10 : (counts * 5)),
].compact.sum

You could use an instance method in your model:
#app/models/model.rb
class Model < ActiveRecord::Base
def percentage
value = 0
values = [[:date_of_birth, 15], [:gender, 15], [:relationship_status,10], [:language,10], [:qualification, 10]]
values.each do |attr,val|
value += val if self.send(attr).present?
end
value += self.interests.count >= 10 ? 10 : self.interests.count*5 if self.interests.present?
# Rails should return the value of the last line, which is the "value" var
end
end
This would allow you to use #user.percentage, where #user is your instance var for the model.

Personally, I don't think that "less lines" is a good idea, but if you want your code in less lines, you can write it like this:
percentage = 0; if date_of_birth.present? then percentage += 15 end; if gender.present? then percentage += 15 end; if relationship_status.present? then percentage += 10 end; if language.present? then percentage += 10 end; if qualification.present? then percentage += 10 end; if interests.present? then if interests.count >= 10 then percentage += 10 else percentage += interests.count*5 end end
In Ruby, you can (almost) always replace linebreaks with semicolons to make your code fit on less lines. In fact, every Ruby program can always be written on a single line.

inc_att = ["date_of_birth", "gender", "relationship_status" , "language", "qualification", "interests"]
inc_att.each do |s|
if self[s].present? && (s == "date_of_birth" || s == "gender")
percentage += 15
elsif self[s].present? && s == "interests" && self[s].count < 10
percentage += self[s].count * 5
else
percentage += 10 if self[s].present?
end
end
Have a look into it

inc_att = ["date_of_birth", "gender", "relationship_status" , "language", "qualification", "interests"]
inc_att.each do |s|
if self[s].present? && (s == "date_of_birth" || s == "gender")
percentage += 15
elsif self[s].present? && s == "interests" && self[s].count < 10
percentage += self[s].count * 5
else
percentage += 10 if self[s].present?
end
end

Inspired by #sawa's answer:
counts = interests.count.to_i
percentage = (counts >= 10 ? 10 : (counts * 5)) +
[
date_of_birth.present? && 15,
gender.present? && 15,
relationship_status.present? && 10,
language.present? && 10,
qualification.present? && 10,
].select(&:itself).sum

Related

Shortening a long if else statement

I have a long if else statement:
rnd = rand(1..1000)
if rnd >= 600
0
elsif rnd < 600 && rnd >= 350
1
elsif rnd < 350 && rnd >= 270
2
elsif rnd < 270 && rnd >= 200
3
elsif rnd < 200 && rnd >= 150
4
elsif rnd < 150 && rnd >= 100
5
elsif rnd < 100 && rnd >= 80
6
elsif rnd < 80 && rnd >= 50
7
elsif rnd < 50 && rnd >= 30
8
else
9
end
I would like to shorten it. Is it possible?
My rubocop swears at this long method.
I would start with something like this:
RANGES = {
(0...30) => 9,
(30...50) => 8,
(50...80) => 7,
# ...
(350...600) => 1,
(600...1000) => 0
}
rnd = rand(1..1000)
RANGES.find { |k, _| k.cover?(rnd) }.last
Great answers already! Just chiming in since I had a suspicion that ruby could handle this with a case statement, and it appears to be able to do so:
rnd = rand(1..1000)
case rnd
when 600.. then 0
when 350...600 then 1
when 270...350 then 2
...
else 9
end
Regardless of the approach taken, you're going to have to specify the ranges somewhere, so I think using something like a case statement is appropriate here (sorry! It doesn't shorten the code more than a few lines). Using a hash would also be a great approach (and might allow you to move the hash elsewhere), as other commenters have already shown.
It's worth mentioning, with ruby ranges, .. means that the range is inclusive and includes the last value (1..10 includes the number 10), and ... means the range is exclusive where it does not include the last value.
The top case 600.. is an endless range, which means it will match anything greater than 600. (That functionality was added in ruby 2.6)
You can simplify your conditions by using only the lower bound.
And you can avoid repeting elsif because it is cumbersome
rnd = rand(1..1000)
lower_bounds = {
600 => 0,
350 => 1,
270 => 2,
200 => 3,
150 => 4,
100 => 5,
80 => 6,
50 => 7,
30 => 8,
0 => 9,
}
lower_bounds.find { |k, _| k <= rnd }.last
MX = 1000
LIMITS = [600, 350, 270, 200, 150, 100, 80, 50, 30, 0]
The required index can be computed as follows.
def doit
rnd = rand(1..MX)
LIMITS.index { |n| n <= rnd }
end
doit
#=> 5
In this example rnd #=> 117.
If this must be repeated many times, and speed is paramount, you could do the following.
LOOK_UP = (1..MX).each_with_object({}) do |m,h|
h[m] = LIMITS.index { |n| n <= m }
end
#=> {1=>9, 2=>9,..., 29=>9,
# 30=>8, 31=>8,..., 49=>8,
# ...
# 600=>0, 601=>0,..., 1000=>0}
Then simply
def doit
LOOK_UP[rand(1..MX)]
end
doit
#=> 3
In this example rand(1..MX) #=> 262.
If speed were paramount but MX were so large that the previous approach would require excessive memory, you could use a binary search.
def doit
rnd = rand(1..MX)
LIMITS.bsearch_index { |n| n <= rnd }
end
doit
#=> 5
In this example rnd #=> 174.
See Array#bsearch_index. bsearch_index returns the correct index in O(log n), n being LIMITS.size). bsearch_index requires the array on which it operates to be ordered.

How can I make query simpler?

I am creating a Rails 5 app.
In this app I got a method that gets values from child objects and adds them to an hash. The below method/code works perfectly fine but I how can I make it better in terms of speed and structure?
def generated_values(period, year, month, quarter)
count = 0
score = 0
actual = 0
goal = 0
red = 0
if stype == "measure"
measures.period(period, year, month, quarter).each do |measure|
count += 1
score += measure.score
actual += measure.value_actual
goal += measure.value_goal
red += measure.value_redflag
end
elsif stype == "objective"
children.each do |child|
child.measures.period(period, year, month, quarter).each do |measure|
count += 1
score += measure.score
actual += measure.value_actual
goal += measure.value_goal
red += measure.value_redflag
end
end
elsif stype == "scorecard"
children.each do |child|
child.children.each do |child2|
child2.measures.period(period, year, month, quarter).each do |measure|
count += 1
score += measure.score
actual += measure.value_actual
goal += measure.value_goal
red += measure.value_redflag
end
end
end
end
values = { :score => score == 0 ? 0 : (score / count).round, :actual => actual, :goal => goal, :red => red }
end
I think I would be tempted to do something like:
def generated_values(period, year, month, quarter)
case stype
when "measure"
selected_measures = measures
when "objective"
selected_measures = child_measures
when "scorecard"
selected_measures = grandchild_measures
end
count = selected_measures.count
{
score: count > 0 ? (selected_measures.sum(:score)/count).round : 0,
actual: selected_measures.sum(:value_actual)
goal: selected_measures.sum(:value_goal)
red: selected_measures.sum(:value_redflag)
}
end
Untested and off-the-cuff.
Naturally, the most interesting part is the selected_measures = bits. But, you haven't provided enough information to help with the proper formulation of those queries.

Rails rounding decimal to the nearest power of ten

I'm looking for a rails function that could return the number to the nearest power of ten(10,100,1000), and also need to support number between 0 and 1 (0.1, 0.01, 0.001):
round(9) = 10
round(19) = 10
round(79) = 100
round(812.12) = 1000
round(0.0321) = 0.01
round(0.0921) = 0.1
I've looking on : Round number down to nearest power of ten
the accepted answer using the length of the string, that can't applied to number between 0 and 1.
updated
Round up to nearest power of 10 this one seems great. But I still can't make it work in rails.
I'm not sure about any function which automatically rounds the number to the nearest power of ten. You can achieve it by running the following code:
def rounded_to_nearest_power_of_ten(value)
abs_value = value.abs
power_of_ten = Math.log10(abs_value)
upper_limit = power_of_ten.ceil
lower_limit = power_of_ten.floor
nearest_value = (10**upper_limit - abs_value).abs > (10**lower_limit - abs_value).abs ? 10**lower_limit : 10**upper_limit
value > 0 ? nearest_value : -1*nearest_value
end
Hope this helps.
Let's simplify your problem to the following form - let the input numbers be in the range [0.1, 1), how would rounding of such numbers look like then?
The answer would be simple - for numbers smaller than 0.5 we would return the number 0.1, for larger numbers it would be 1.0.
All we have to do is to make sure that our number will be in that range. We will "move" decimal separator and remember how many moves we made in second variable. This operation is called normalization.
def normalize(fraction)
exponent = 0
while fraction < (1.0/10.0)
fraction *= 10.0
exponent -= 1
end
while fraction >= 1.0
fraction /= 10.0
exponent += 1
end
[fraction, exponent]
end
Using above code you can represent any floating number as a pair of normalized fraction and exponent in base 10. To recreate original number we will move decimal point in opposite direction using formula
original = normalized * base^{exponent}
With data property normalized we can use it in our simple rounding method like that:
def round(number)
fraction, exponent = normalize(number)
if fraction < 0.5
0.1 * 10 ** exponent
else
1.0 * 10 ** exponent
end
end
if the number is >= 1.0, this should work.
10 ** (num.floor.to_s.size - ( num.floor.to_s[0].to_i > 4 ? 0 : 1))
Try this:
def round_tenth(a)
if a.to_f >= 1
return 10 ** (a.floor.to_s.size - ( a.floor.to_s[0].to_i > 4 ? 0 : 1))
end
#a = 0.0392
c = a.to_s[2..a.to_s.length]
b = 0
c.split('').each_with_index do |s, i|
if s.to_i != 0
b = i + 1
break
end
end
arr = Array.new(100, 0)
if c[b-1].to_i > 4
b -= 1
if b == 0
return 1
end
end
arr[b-1] = 1
return ("0." + arr.join()).to_f
end
class Numeric
def name
def helper x, y, z
num = self.abs
r = 1
while true
result = nil
if num.between?(x, y)
if num >= y/2.0
result = y.round(r+1)
else
result = x.round(r)
end
return self.negative? ? -result : result
end
x *= z; y *= z; r += 1
end
end
if self.abs < 1
helper 0.1, 1, 0.1
else
helper 1, 10, 10
end
end
end
Example
-0.049.name # => -0.01
12.name # => 10
and so on, you are welcome!

Opposite of Ruby's number_to_human

Looking to work with a dataset of strings that store money amounts in these formats. For example:
$217.3M
$1.6B
$34M
€1M
€2.8B
I looked at the money gem but it doesn't look like it handles the "M, B, k"'s back to numbers. Looking for a gem that does do that so I can convert exchange rates and compare quantities. I need the opposite of the number_to_human method.
I would start with something like this:
MULTIPLIERS = { 'k' => 10**3, 'm' => 10**6, 'b' => 10**9 }
def human_to_number(human)
number = human[/(\d+\.?)+/].to_f
factor = human[/\w$/].try(:downcase)
number * MULTIPLIERS.fetch(factor, 1)
end
human_to_number('$217.3M') #=> 217300000.0
human_to_number('$1.6B') #=> 1600000000.0
human_to_number('$34M') #=> 34000000.0
human_to_number('€1M') #=> 1000000.0
human_to_number('€2.8B') #=> 2800000000.0
human_to_number('1000') #=> 1000.0
human_to_number('10.88') #=> 10.88
I decided to not be lazy and actually write my own function if anyone else wants this:
def text_to_money(text)
returnarray = []
if (text.count('k') >= 1 || text.count('K') >= 1)
multiplier = 1000
elsif (text.count('M') >= 1 || text.count('m') >= 1)
multiplier = 1000000
elsif (text.count('B') >= 1 || text.count('b') >= 1)
multiplier = 1000000000
else
multiplier = 1
end
num = text.to_s.gsub(/[$,]/,'').to_f
total = num * multiplier
returnarray << [text[0], total]
return returnarray
end
Thanks for the help!

Using Ruby convert numbers to words?

How to convert numbers to words in ruby?
I know there is a gem somewhere. Trying to implement it without a gem. I just need the numbers to words in English for integers. Found this but it is very messy. If you have any idea on how to implement a cleaner easier to read solution please share.
http://raveendran.wordpress.com/2009/05/29/ruby-convert-number-to-english-word/
Here is what I have been working on. But having some problem implementing the scales. The code is still a mess. I hope to make it more readable when it functions properly.
class Numberswords
def in_words(n)
words_hash = {0=>"zero",1=>"one",2=>"two",3=>"three",4=>"four",5=>"five",6=>"six",7=>"seven",8=>"eight",9=>"nine",
10=>"ten",11=>"eleven",12=>"twelve",13=>"thirteen",14=>"fourteen",15=>"fifteen",16=>"sixteen",
17=>"seventeen", 18=>"eighteen",19=>"nineteen",
20=>"twenty",30=>"thirty",40=>"forty",50=>"fifty",60=>"sixty",70=>"seventy",80=>"eighty",90=>"ninety"}
scale = [000=>"",1000=>"thousand",1000000=>" million",1000000000=>" billion",1000000000000=>" trillion", 1000000000000000=>" quadrillion"]
if words_hash.has_key?(n)
words_hash[n]
#still working on this middle part. Anything above 999 will not work
elsif n>= 1000
print n.to_s.scan(/.{1,3}/) do |number|
print number
end
#print value = n.to_s.reverse.scan(/.{1,3}/).inject([]) { |first_part,second_part| first_part << (second_part == "000" ? "" : second_part.reverse.to_i.in_words) }
#(value.each_with_index.map { |first_part,second_part| first_part == "" ? "" : first_part + scale[second_part] }-[""]).reverse.join(" ")
elsif n <= 99
return [words_hash[n - n%10],words_hash[n%10]].join(" ")
else
words_hash.merge!({ 100=>"hundred" })
([(n%100 < 20 ? n%100 : n.to_s[2].to_i), n.to_s[1].to_i*10, 100, n.to_s[0].to_i]-[0]-[10])
.reverse.map { |num| words_hash[num] }.join(" ")
end
end
end
#test code
test = Numberswords.new
print test.in_words(200)
My take on this
def in_words(int)
numbers_to_name = {
1000000 => "million",
1000 => "thousand",
100 => "hundred",
90 => "ninety",
80 => "eighty",
70 => "seventy",
60 => "sixty",
50 => "fifty",
40 => "forty",
30 => "thirty",
20 => "twenty",
19=>"nineteen",
18=>"eighteen",
17=>"seventeen",
16=>"sixteen",
15=>"fifteen",
14=>"fourteen",
13=>"thirteen",
12=>"twelve",
11 => "eleven",
10 => "ten",
9 => "nine",
8 => "eight",
7 => "seven",
6 => "six",
5 => "five",
4 => "four",
3 => "three",
2 => "two",
1 => "one"
}
str = ""
numbers_to_name.each do |num, name|
if int == 0
return str
elsif int.to_s.length == 1 && int/num > 0
return str + "#{name}"
elsif int < 100 && int/num > 0
return str + "#{name}" if int%num == 0
return str + "#{name} " + in_words(int%num)
elsif int/num > 0
return str + in_words(int/num) + " #{name} " + in_words(int%num)
end
end
end
puts in_words(4) == "four"
puts in_words(27) == "twenty seven"
puts in_words(102) == "one hundred two"
puts in_words(38_079) == "thirty eight thousand seventy nine"
puts in_words(82102713) == "eighty two million one hundred two thousand seven hundred thirteen"
Have you considered humanize ?
https://github.com/radar/humanize
Simple answer use humanize gem and you will get desired output
Install it directly
gem install humanize
Or add it to your Gemfile
gem 'humanize'
And you can use it
require 'humanize'
1.humanize #=> 'one'
345.humanize #=> 'three hundred and forty-five'
1723323.humanize #=> 'one million, seven hundred and twenty-three thousand, three hundred and twenty-three'
If you are using this in rails you can directly use this
NOTE: As mentioned by sren in the comments below. The humanize method provided by ActiveSupport is different than the gem humanize
You can also use the to_words gem.
This Gem converts integers into words.
e.g.
1.to_words # one ,
100.to_words # one hundred ,
101.to_words # one hundred and one
It also converts negative numbers.
I can see what you're looking for, and you may wish to check out this StackOverflow post: Number to English Word Conversion Rails
Here it is in summary:
No, you have to write a function yourself. The closest thing to what
you want is number_to_human, but that does not convert 1 to One.
Here are some URLs that may be helpful:
http://codesnippets.joyent.com/posts/show/447
http://raveendran.wordpress.com/2009/05/29/ruby-convert-number-to-english-word/
http://deveiate.org/projects/Linguistics/
I am not quite sure, if this works for you. Method can be called like this.
n2w(33123) {|i| puts i unless i.to_s.empty?}
Here is the method ( I have not tested it fully. I think it works upto million. Code is ugly, there is a lot of room for re-factoring. )
def n2w(n)
words_hash = {0=>"zero",1=>"one",2=>"two",3=>"three",4=>"four",5=>"five",6=>"six",7=>"seven",8=>"eight",9=>"nine",
10=>"ten",11=>"eleven",12=>"twelve",13=>"thirteen",14=>"fourteen",15=>"fifteen",16=>"sixteen",
17=>"seventeen", 18=>"eighteen",19=>"nineteen",
20=>"twenty",30=>"thirty",40=>"forty",50=>"fifty",60=>"sixty",70=>"seventy",80=>"eighty",90=>"ninety"}
scale = {3=>"hundred",4 =>"thousand",6=>"million",9=>"billion"}
if words_hash.has_key?n
yield words_hash[n]
else
ns = n.to_s.split(//)
while ns.size > 0
if ns.size == 2
yield("and")
yield words_hash[(ns.join.to_i) - (ns.join.to_i)%10]
ns.shift
end
if ns.size > 4
yield(words_hash[(ns[0,2].join.to_i) - (ns[0,2].join.to_i) % 10])
else
yield(words_hash[ns[0].to_i])
end
yield(scale[ns.size])
ns.shift
end
end
end
def subhundred number
ones = %w{zero one two three four five six seven eight nine
ten eleven twelve thirteen fourteen fifteen
sixteen seventeen eighteen nineteen}
tens = %w{zero ten twenty thirty **forty** fifty sixty seventy eighty ninety}
subhundred = number % 100
return [ones[subhundred]] if subhundred < 20
return [tens[subhundred / 10]] if subhundred % 10 == 0
return [tens[subhundred / 10], ones[subhundred % 10]]
end
def subthousand number
hundreds = (number % 1000) / 100
tens = number % 100
s = []
s = subhundred(hundreds) + ["hundred"] unless hundreds == 0
s = s + ["and"] unless hundreds == 0 or tens == 0
s = s + [subhundred(tens)] unless tens == 0
end
def decimals number
return [] unless number.to_s['.']
digits = number.to_s.split('.')[1].split('').reverse
digits = digits.drop_while {|d| d.to_i == 0} . reverse
digits = digits.map {|d| subhundred d.to_i} . flatten
digits.empty? ? [] : ["and cents"] + digits
end
def words_from_numbers number
steps = [""] + %w{thousand million billion trillion quadrillion quintillion sextillion}
result = []
n = number.to_i
steps.each do |step|
x = n % 1000
unit = (step == "") ? [] : [step]
result = subthousand(x) + unit + result unless x == 0
n = n / 1000
end
result = ["zero"] if result.empty?
result = result + decimals(number)
result.join(' ').strip
end
def words_from_numbers(number)
ApplicationHelper.words_from_numbers(number)
end
Its been quite a while since the question was asked. Rails has something inbuilt for this now.
https://api.rubyonrails.org/classes/ActionView/Helpers/NumberHelper.html
number_to_human(1234567) # => "1.23 Million"
number_to_human(1234567890) # => "1.23 Billion"
number_to_human(1234567890123) # => "1.23 Trillion"
number_to_human(1234567890123456) # => "1.23 Quadrillion"
number_to_human(1234567890123456789) # => "1230 Quadrillion"

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