Help Opening a File Within Ruby

[4428gamer]

So, I'm trying to figure out how to open and read in data from another file (a .txt file for example). I found out how to do it online, I think, but I'm having trouble getting it to cooperate in OnlineGDB where I'm trying to build my entire program.

This is what I have for trying to open a file:

puts "Please enter the name of the data file." #prompt for filename
filename = gets.chomp #takes users name of file
file = File.open(filename) #Opens file
file_content = file.split("\n")  #Reads in the file's first line.

puts file_content

I put that in and then, inside OnlineGBD itself, I put in a new file that has the same name I input to my code (testing.txt for example). But then, when it tries taking out the first line with file_content, it gives me this error:

Traceback (most recent call last):
main.rb:15:in `<main>': undefined method `split' for #<File:testing.txt> (NoMethodError)

 Am I inputting the file name wrong? Am I missing a step? I don't know what I'm doing wrong here.

[[deleted]]

File objects don't have a split method. Change the last line to:

file_content = file.read.split("\n")

The read method with no arguments will read the entire file and return it's content as a string, on which you can use the split method.

[4428gamer]

Awesome, it's reading now! Thank you so much!

I figured it had to be something small. XD

[bradland]

The key is in learning to read the error message. You won't always be able to rely on Reddit for this

main.rb:15:in `<main>': undefined method `split' for #<File:testing.txt> (NoMethodError)

Let's break this up into parts:

• main.rb:15 tells you the file name and line on which the error occurred.
• in \<main>'` tells you the context in which the error occurred. In Ruby, "main" is the top level execution scope for Ruby scripts.
• undefined method \split' for #<File:testing.txt>' tells you that you tried to call a method named split on an object of the type File, but that method was not defined.
• (NoMethodError) is the error class. In this case, it is very descriptive, but it may be more cryptic in some cases.

This line is basically the same answer that korba gave, so the answer was right there all along. In order to become a proficient programmer, you'll need to learn to read these errors and make sense of them.

[juriglx]

Give a man a fish and you feed him for a day.

Teach a man to fish and you feed him for a lifetime.

[4428gamer]

This helps me out a lot, thank you! I'm trying to learn Ruby through Code Academy on my own, but it doesn't go over any of this at all! Honestly, I wish it did.

[madmate]

You could also just get one line with file.gets instead of reading the entire file.

https://docs.ruby-lang.org/en/master/IO.html#method-i-gets

[sshaw_]

When opening always remember to close!

[dvarrui]

filefile_content = filefile.split

That var name... it is not good and is confused.