Reputation: 4173
I am trying to learn Ruby and I am trying to call one instance method from another. My code is as follows:
class ScanTextInFile
attr_accessor :content , :line_number
def content
@content
end
def line_number
@line_number
end
def content= (text)
@content = text
end
def line_number= (line)
@line_number = line
end
def initialize (content , line_number)
self.content = content
self.line_number = line_number
#self.calculate_word_frequency
end
def calculate_word_frequency
words = self.content.split
words_hash = Hash.new
words.each do | word |
word.downcase!
if words_hash.has_key?
words_hash[key] += 1
else
words_hash[key] = 1
end
highest_wf_count = words_hash.values.max
words_hash.each { |key, value| highest_wf_words.push(key) }
end
end
end
I am trying to calculate the number of times a word appears in a given string. I am using the instance method calculate_word_frequency
for that. When I comment out the call to calculate_word_frequency
the code runs fine
$ irb -I
irb(main):001:0> require_relative 'test'
=> true
irb(main):002:0>
irb(main):003:0*
irb(main):004:0* a = ScanTextInFile.new("Bla bla foo foo bar baz foo bar bar", 1)
=> #<ScanTextInFile:0x007fc7a39b01c8 @content="Bla bla foo foo bar baz foo bar bar", @line_number=1>
However, when I call the instance method calculate_word_frequency
in the initialize
block, I get an error saying ArgumentError: wrong number of arguments (0 for 1)
$ irb -I
irb(main):001:0> require_relative 'test'
=> true
irb(main):002:0> a = ScanTextInFile.new("Bla bla foo foo bar baz foo bar bar", 1)
ArgumentError: wrong number of arguments (0 for 1)
I tried removing the self
while calling the method but I still get error. I don't know what's going wrong when I make the call to the method. What is the correct way to do this?
Upvotes: 2
Views: 189
Reputation: 15997
The error is pretty descriptive here, on line 32 you have this:
if words_hash.has_key?
The method Hash#has_key?
requires you pass in one argument, as in some_hash.has_key?("a_key")
I think you mean to use it like this: words_hash.has_key?(word)
.
Upvotes: 2
Reputation: 8477
If you're using attr_accessor
, you don't need to define getters and setters for your instance variables. The whole point of using attr_accessor
is that it does it for you. :) Also, getters and setters are generally only used by external classes and modules to access instances variables; within the class, just access the instance variables directly. Finally, you're not telling has_key?
the key to look for, you're mixing up key
and word
, and you're referencing a data structure highest_wf_words
that isn't defined anywhere.
Here's a revised version of your class. I don't understand exactly what you're trying to do—it looks like you're still writing the algorithm—but hopefully this is enough for you to move forward and continue working:
class ScanTextInFile
attr_accessor :content, :line_number
def initialize(content, line_number)
@content = content
@line_number = line_number
calculate_word_frequency
end
def calculate_word_frequency
words_hash = Hash.new(0) # Non-existent keys will default to a value of 0.
highest_wf_words = Array.new
@content.split.each do |word|
words_hash[word.downcase] += 1
highest_wf_count = words_hash.values.max # What is this for?
highest_wf_words.concat(words_hash.keys) # What is this for?
end
p highest_wf_words
end
end
Upvotes: 1
Reputation: 34336
Change this:
if words_hash.has_key?
words_hash[word] += 1
else
words_hash[word] = 1
end
To:
if words_hash.has_key? word
words_hash[word] += 1
else
words_hash[word] = 1
end
You are using Hash#has_key method without providing the key
argument to it, that's why it's failing.
Upvotes: 2