Iterating over loops in ruby? - ruby

Question

I am new to ruby. I am trying to create a letter counter. my intended output was supposed to be [2,"I"] but I keep getting [3,"D]. Any help in understanding where I went wrong would be so helpful, thank you.
class LetterCounter
def initialize(text)
#text = text
end
def calculate_most_common()
counter = Hash.new(1)
most_common = nil
most_common_count = 1
#text.chars.each do |char|
next unless is_letter?(char)
counter[char] = (counter[char] || 1) + 1
if counter[char] > most_common_count
most_common = char
most_common_count += counter[char]
end
end
return [most_common_count, most_common]
end
private
def is_letter?(letter)
return letter =~ /[a-z]/i
end
end
counter = LetterCounter.new("Digital Punk")
p counter.calculate_most_common
# Intended output:
# [2, "i"]

Answer 1

Try:
class LetterCounter
def initialize(text)
#text = text
end
def calculate_most_common()
arr=#text.scan(/[a-z]/i)
arr.each_with_object(Hash.new(0)) { |n,h| h[n] += 1 }.max_by(&:last)
end
end
counter = LetterCounter.new("Digital Punk")
p counter.calculate_most_common
Prints:
["i", 2]
If you want to fix yours, try:
class LetterCounter
def initialize(text)
#text = text
end
def calculate_most_common()
counter = Hash.new(0)
most_common = nil
most_common_count = 0
#text.chars.each do |char|
next unless is_letter?(char)
counter[char] += 1
if counter[char]>most_common_count
most_common=char
most_common_count=counter[char]
end
end
return [most_common_count, most_common]
end
private
def is_letter?(letter)
return letter =~ /[a-z]/i
end
end
counter = LetterCounter.new("Digital Punk")
p counter.calculate_most_common

Answer 2

class LetterCounter
def initialize(text)
#text = text
end
def calculate_most_common()
counter = Hash.new(0) # wrong initialization in your code
most_common = nil
most_common_count = 0
#text.chars.each do |char|
next unless is_letter?(char)
counter[char] = (counter[char] || 1) + 1
puts "#{char} #{counter[char]}"
if counter[char] > most_common_count
puts "most common: #{most_common_count} #{char} #{counter[char]}"
most_common = char
most_common_count = counter[char] # error in your code
end
end
return [most_common_count, most_common]
end
private
def is_letter?(letter)
return letter =~ /[a-z]/i
end
end
counter = LetterCounter.new("Digital Punk")
p counter.calculate_most_common

Answer 3

The initial counters are at 1. These should be 0 since you are incrementing inside your loop anyways.
On the First Iteration -
Hash counter[char] is being initialized to 1 ( From Hash.new(1) ),
Then counter[char] is increased to 1 on first loop and the most_common_count is also increased by 1.
Which leads to D having value 3.
since most_common_count is already at 3 - the loop would no longer go into the if condition - as other characters would reach only 2 ( 1 from Hash.new and 1 from counter[char] +1 )
The if condition is > most_common_count and not >= - hence even if i reaches 3 - condition would not execute.
Hence the output [3, 'D']
Try this instead :
class LetterCounter
def initialize(text)
#text = text
end
def calculate_most_common()
counter = Hash.new(0)
most_common = nil
most_common_count = 0
#text.chars.each do |char|
next unless is_letter?(char)
puts char + " ==> " + counter[char].to_s # To know the value on each iteration
counter[char] += 1
if counter[char] > most_common_count
most_common = char
most_common_count = counter[char]
puts [most_common_count, most_common] # To know when the if condition is executed
end
end
return [most_common_count, most_common]
end
private
def is_letter?(letter)
return letter =~ /[a-z]/i
end
end
counter = LetterCounter.new("Digital Punk")
p counter.calculate_most_common