ruby filename path to string error - ruby

Question

This is my code:
file = File.open('result.txt', 'w+').read
path = Dir[ENV['HOME'] + '/Desktop/Test/*.txt']
file.puts "this is a #{path} test: "
It comes up with an error:
C:/Users/User/RubymineProjects/Comparison/test.rb:5:in `<top (required)>': private method `puts' called for "":String (NoMethodError)
from -e:1:in `load'
from -e:1:in `<main>'
my intended result is:
this is a C:/Users/User/Desktop/Test/new_1.txt test:
i've tried this:
puts "this is a #{path[0]} test: "
which achieves what i want but as soon as i do file.puts it comes up with the same error again.

Answer 1

When you do file.puts here, you're sending a method #puts to a string object that's now stored in the variable file. This is because File#read method returns a string. So, on the first line, file takes the contents of the result.txt and then stores it in the variable file. Then you're callingputson that string. AndString#puts` is a private method, so you can't use it the way you used it in the code above.
If your intention is to write the result this is a C:/Users/User/Desktop/Test/new_1.txt test:, then you need to use the File.open method this way:
File.open('result.txt', 'w+') do |file|
path = Dir[ENV['HOME'] + '/Desktop/Test/*.txt']
file.puts "this is a #{path} test: "
# whatever else needs to be written goes here
end
Or, if you prefer the imperative style instead of the block style:
file = File.new('result.txt', 'w+')
# If you prefer `open`, that works too!
# file = File.open('result.txt', 'w+')
path = Dir[ENV['HOME'] + '/Desktop/Test/*.txt']
file.puts "this is a #{path} test: "
# ensure this is closed, or you'll have memory issues if you do this often
file.close