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I am following a beginners course on Ruby, trying to define two methods in the editor:
A greeter method that takes a single string parameter, name, and returns a string greeting that person. (Make sure to use return and don't use print or puts.)
A by_three? method that takes a single integer parameter, number, and returns true if that number is evenly divisible by three and false if not.
The error I'm getting is "unexpected end".
def greeter(name)
return "hey" + name + "how are you" + "."
end
greeter(alan)
def by_three?(number)
if number % 3 == 0
return true
else
return false
end
by_three?(12)
You should terminate if statement with end keyword:
def by_three?(number)
if number % 3 == 0
return true
else
return false
end
end
Having said that, this method is written really bad, and it can be much simpler:
def by_three?(number)
number % 3 == 0
end
Related
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I'm very puzzled with this simple method I have where I'm just trying to puts a character of an array if, when compared with the character of another array, it is different.
This works with the == operator but not with the !=
Maybe it has to do with the each loops but I can't see what the error is. Any ideas?
Thanks
def remove_vowels(s)
nw_s = s.chars
vowels = "aeiou".chars
result = []
nw_s.each do |char|
vowels.each do |vowel|
if char != vowel
print char
end
end
end
end
remove_vowels("apple")
Nested each is no ruby way of doing this kind of task. You can write this
def remove_vowels(s)
nw_s = s.chars
vowels = "aeiou".chars
result = nw_s.map {|k| k unless vowels.include?(k) }.compact
end
remove_vowels("apple")
One line of code instead seven
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I am being asked to:
Define a method called first_longer_than_second with a parameter called first and another called second. The method will return true if the first word passed in is greater than or equal to the length of the second word. It returns false otherwise.
This is the code I have come up with:
def first_longer_than_second(first, second)
if first >= second
return true;
else
return false;
end
end
The calls I am making:
first_longer_than_second('pneumonoultramicroscopicsilicovolcanoconiosis', 'k') #=> false
first_longer_than_second('apple', 'prune') #=> true
For some reason on repl.it I only get the output false
And i get this error message on the platform I am actually meant to be completing this task on:
expected #<TrueClass:20> => true
got #<FalseClass:0> => false
Compared using equal?, which compares object identity,
but expected and actual are not the same object. Use
`expect(actual).to eq(expected)` if you don't care about
object identity in this example.
exercise_spec.rb:42:in `block (2 levels) in <top (required)>'
Tried a number of things, but annoyingly stuck with something that seems should be simple...
Define a method called first_longer_than_second with a parameter called first and another called second. The method will return true if the first word passed in is greater than or equal to the length of the second word. It returns false otherwise.
Your code:
def first_longer_than_second(first, second)
if first >= second
return true;
else
return false;
end
end
First of all, your code doesn't follow the requirements. They ask to compare the lengths of the two arguments. The if condition should be:
if first.length >= second.length
See the documentation of String#length.
Regarding the syntax of Ruby, the semicolons (;) after the statements are not needed. Like in Javascript, a Ruby statement can be terminated using a semicolon but also a newline. The semicolon is useful to separate two statements on the same line.
Next, the same as in Javascript (and many other languages), you can directly return the result of the comparison (and not put it into an if statement that returns true/false):
def first_longer_than_second(first, second)
return first.length >= second.length
end
One last improvement to make it look like Ruby (and not Javascript or PHP): a Ruby function returns the value of the last expression it computes; this makes the presence of the return keyword superfluous here.
Your code should be:
def first_longer_than_second(first, second)
first.length >= second.length
end
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I have two methods turn_count(board) and current_player(board). The turn_count(board) method, which returns the number of "X"s and "O"s in an array is working appropriately. But the current_player(board) method, which is supposed to puts "X" if turn_count(board) is even and "O" if turn_count(board) is odd keeps giving me an error. The error is:
/Users/john/Desktop/test file.rb:13:in current_player': undefined method%' for nil:NilClass (NoMethodError)
from /Users/john/Desktop/test file.rb:18:in `'
Clearly it's saying there's an issue with the modulo operator being used, but i'm not sure why and have been wracking my brain trying to figure it out.
Any help is greatly appreciated!
def turn_count(board)
count = 0
board.each do |x| if x == "X" || x == "O"
count = count + 1
end
end
puts count
end
def current_player(board)
if turn_count(board) % == 0
puts "X"
else
puts "O"
end
end
The problem is you are using % on a NilClass. Your turn_count() method returns nil. Check what happens if you replace puts count with count.
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Hello I am writing a code for a simple die of (n) sides and it works fine:
class Die
def initialize(sides)
#sides = sides
raise ArgumentError if sides < 1
end
def roll
roll_number = rand(#sides) + 1
end
end
However, when I change my initialized variable from instance to class the random numbers generated go from integers to a bunch of small floating point numbers around 1.
class Die
def initialize(sides)
HERE --> ##sides = sides
raise ArgumentError if sides < 1
end
def roll
roll_number = rand(#sides) + 1
end
end
I wanted to know what may cause this difference?
In the second code snippet, you're initializing the class variable ##sides but still passing the instance variable #sides to rand(). Since #sides is not initialized, you are passing nil to the call to rand(), so Kernel#rand gives a float instead of integer.
There's an error in your code, in your second version of Die you actually never call the right variable in your roll method.
It should be:
def roll
roll_number = rand(##sides) + 1
end
Instead yours was evaluating to:
roll_number = rand(nil) + 1
According to the rand library if you don't supply an argument rand returns a pseudo-random floating point number between 0.0 and 1.0, including 0.0 and excluding 1.0.
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Just started to go through the 7 languages in 7 weeks book; day one problem make a simple higher or lower game in ruby. When I execute my script I get the following error but I don't know why.
EDIT: This is thrown after I guess once.
NameError: undefined local variable or method actual' for main:Object
from guess_game.rb:2:inguess'
from guess_game.rb:22
def guess(guess, acutal)
unless guess == actual
if guess > actual
puts 'Lower'
else
puts 'Higher'
return false
end
end
puts 'Correct'
return true
end
answer = rand(10)
game_won = false
puts 'I am thinking of a number, what is it?'
until game_won
num = gets.to_i
# Static Debug Line
puts "Guess #{num} : Answer #{answer}"
game_won = guess(num, answer)
end
def guess(guess, actual)
unless guess == actual
if guess > actual
puts 'Lower'
else
puts 'Higher'
return false
end
end
puts 'Correct'
return true
end
Problem: Spelling mistake, Corrected