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Day 16 of 30 Ruby Coding Challenge - Sum Even Numbers in a Fibonacci Sequence
Hey friends!
This is the blog post version of the Youtube video from the 30 Ruby Coding Challenges in 30 Days series
We’ve solved the Fibonacci sequence here, here and here, which means that we have some clues of how to create a Fibonacci sequence :)
Today we want to be a little bit daring by solving the following problem:
I want to sum all even numbers in a Fibonacci sequence
Fibonacci Sequence in Ruby
As you already know, this is one of the solutions:
Ruby
1
def fibonacci_sum(count)
2
number = 0
3
sequence = []
4
(0..count).each do |item|
5
number = item if item <= 1
6
number = sequence[-1] + sequence[-2] if item > 1
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sequence << number
8
end
9
sequence
10
end
We’re returning a Fibonacci sequence, however, that’s not what we’re looking for
Sum Even Numbers in a Fibonacci Sequence in Ruby
We’re going to:
- add a local variable called sum
- then update this variable only if the number is even
- return the sum variable
Ruby
1
def fibonacci_sum(count)
2
sum = 0
3
number = 0
4
sequence = []
5
(0..count).each do |item|
6
number = item if item <= 1
7
number = sequence[-1] + sequence[-2] if item > 1
8
sequence << number
9
10
sum += number if number % 2 == 0
11
end
12
sum
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end
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