CODEWITHSUNDEEP
arraysruby-on-railsrubymath
Smeterlink
Smeterlink

Reputation: 796

Convert array of strings to array of floats in Ruby to get mean/average value

I have a file.txt with a float value on each line:

23.45
12.01
15
900.6543

I want to get the mean/average of these values, so I read them text. Here's my script.rb:

#!/usr/bin/ruby
require 'bigdecimal'
require 'bigdecimal/util'
array = IO.readlines 'file.txt'
array.map(&:to_f)
numerator = array.reduce(0) { |a, v| a + v }
denominator = array.count
mean = numerator.to_f / denominator.to_f
puts mean

I get the following error with ruby script.rb:

Traceback (most recent call last):
        4: from list2.rb:7:in `<main>'
        3: from list2.rb:7:in `reduce'
        2: from list2.rb:7:in `each'
        1: from list2.rb:7:in `block in <main>'
list2.rb:7:in `+': String can't be coerced into Integer (TypeError)

Any suggestions?

Upvotes: 0

Views: 221

Answers (1)

Chris
Chris

Reputation: 36620

When you used array.map(&:to_f) you created a new array of floats... that you did nothing with. You either want to assign that to a variable and use it, or use #map! to modify array.

array.map!(&:to_f)

Upvotes: 1

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