I am trying to create a program that will count the word frequency within a text file that I have created. I have a text file titled moms_letter.txt and this is my code:
word_count = {}
File.open("moms_letter.txt", "r") do |f|
f.each_line do |line|
words = line.split(' ').each do |word|
word_count[word] += 1 if word_count.has_key? word
word_count[word] = 1 if not word_count.has_key? word
end
end
end
puts word_count
The problem I am getting is when I go to run the file, I get the error:
there is no such file or directory - moms_letter.txt (Errno: : ENOENT)
Not quite sure why this is occurring when I have the text file created.
Any help is appreciated.
I am also newbie in Ruby, so thanks for the patience.
You must be executing your program from outside the directory where your moms_letter.txt file resides. You need to use an absolute path to open your file. Or, execute your program always from the directory where the .txt is. So, instead of using "moms_letter.txt" go with "complete/path/to/file/moms_letter.txt".
I'm fairly new to Ruby too, but have worked with text files a bit recently. It may seem like an obvious question, but is the text file you're trying to open in the same directory as your .rb file? Otherwise you'll need to include the relative path to it.
For troubleshooting sake, try File.new("temp.txt", "w") and then File.open("temp.txt", "r") to see if that works. Then you'll know if it's an issue with your code or with the txt file you're trying to access.
Also using File.exists?("moms_letter.txt") will help you determine whether you can access that file from within your .rb script.
Hope that helps!
Related
My program reads a configuration file every 3 sec. within a while loop. Once I change the configuration file with an external editor like notepad, my program creates a temporary file for some reason and keeps reading from there.
I want my program to read from the current configuration file in order to have the most recent changes in my program.
What can I do about it?
Simplified code:
while(true)
file = File.open(filename, "r")
data = JSON.parse(file.read) if file
file.close
sleep(3)
end
If you are on linux, you can try linux inotfy service, this is the gem. This is an example of how to use it.
First of all you have to run
gem install ruby-inotify
and then try this code
notifier = Inotify.new
notifier.add_watch(filename, Inotify::CREATE | Inotify::MODIFY)
notifier.each_event do |ev|
file = File.open(filename, "r")
data = JSON.parse(file.read)
file.close
end
If you are open to using a gem for this, use the following.
https://github.com/thomasfl/filewatcher
Usage
FileWatcher.new(["lib/", "Rakefile"]).watch do |filename|
puts "Changed " + filename
end
So, I'm relatively new to programming, and I have started working with ruby. I am going through "Learn how to code the hard way: Ruby" and I am on exercise 15; the beginning of file reading. I have copied the code they provided word for word, literally copy and pasted it to make sure, but I am getting the same error. I've googled the error, but to no avail. I have the .rb file in the same directory as the .txt file I'm trying to read. Here is my code.
filename = ARGV.first
prompt = "> "
txt = File.open(filename)
puts "Here's your file: #{filename}"
puts txt.read()
puts "I'll also ask you to type it again:"
print prompt
file_again = STDIN.gets.chomp()
txt_again = File.open(file_again)
puts txt_again.read()
The error I keep getting it this:
ex15.rb:19:in 'initialize': No such file of directory - ex15.txt <Errno::ENOENT>
from ex15.rb:4:in 'open'
from ex15.rb:4:in '<main>'
command to run it:
ruby ex15.rb ex15.txt
Any help is appreciated. Thanks
When you don't specify the mode argument for File.open(), the default is 'r', which stands for read. And to read a file, it has to exist already. The error message is telling you that there is no file named 'ex15.txt' in the current directory for ruby to read.
To get rid of the error, create a file called ex15.txt in the current directory, and type 'hello world' in the file.
New to Ruby, probably something silly
Trying to make a directory in order to store files in it. Here's my code to do so
def generateParsedEmailFile
apath = File.expand_path($textFile)
filepath = Pathname.new(apath + '/' + #subject + ' ' + #date)
if filepath.exist?
filepath = Pathname.new(filepath+ '.1')
end
directory = Dir.mkdir (filepath)
Dir.chdir directory
emailText = File.new("emailtext.txt", "w+")
emailText.write(self.generateText)
emailText.close
for attachment in #attachments
self.generateAttachment(attachment,directory)
end
end
Here's the error that I get
My-Name-MacBook-2:emails myname$ ruby etext.rb email4.txt
etext.rb:196:in `mkdir': Not a directory - /Users/anthonydreessen/Developer/Ruby/emails/email4.txt/Re: Make it Brief Report Wed 8 May 2013 (Errno::ENOTDIR)
from etext.rb:196:in `generateParsedEmailFile'
from etext.rb:235:in `<main>'
I was able to recreate the error - it looks like email4.txt is a regular file, not a directory, so you can't use it as part of your directory path.
If you switched to mkdir_p and get the same error, perhaps one of the parents named in '/Users/anthonydreessen/Developer/Ruby/emails/email4.txt/Re: Make it Brief Report Wed 8 May 2013' already exists as a regular file and can't be treated like a directory. Probably that last one named email.txt
You've got the right idea, but should be more specific about the files you're opening. Changing the current working directory is really messy as it changes it across the entire process and could screw up other parts of your application.
require 'fileutils'
def generate_parsed_email_file(text_file)
path = File.expand_path("#{#subject} #{date}", text_file)
while (File.exist?(path))
path.sub!(/(\.\d+)?$/) do |m|
".#{m[1].to_i + 1}"
end
end
directory = File.dirname(path)
unless (File.exist?(directory))
FileUtils.mkdir_p(directory)
end
File.open(path, "w+") do |email|
emailText.write(self.generateText)
end
#attachments.each do |attachment|
self.generateAttachment(attachment, directory)
end
end
I've taken the liberty of making this example significantly more Ruby-like:
Using mixed-case names in methods is highly irregular, and global variables are frowned on.
It's extremely rare to see for used, each is much more flexible.
The File.open method yields to a block if the file could be opened, and closes automatically when the block is done.
The ".1" part has been extended to keep looping until it finds an un-used name.
FileUtils is employed to makes sure the complete path is created.
The global variable has been converted to an argument.
Is there a way to edit each line in a file, without involving 2 files? Say, the original file has,
test01
test02
test03
I want to edit it like
test01,a
test02,a
test03,a
Tried something as show in the code block, but it replaces some of the characters.
Writing it to a temporary file and then replace the original file works, However, I need to edit the file quite often and therefore prefer to do it within the file itself .Any pointers are appreciated.
Thank you!
File.open('mytest.csv', 'r+') do |file|
file.each_line do |line|
file.seek(-line.length, IO::SEEK_CUR)
file.puts 'a'
end
end
f = open 'mytest.csv', 'r+'
r = f.readlines.map { |e| e.strip << ',a' }
f.rewind
f.puts r
f.close # you can leave out this line if it's the last one that runs
Here is a one-liner variation, note that in this case 2 descriptors are left open until the program exits.
open(F='mytest.csv','r+').puts open(F,'r').readlines.map{|e|e.strip<<',a'}
Writing to a file doesn't insert; it always overwrites. This makes it awkward to modify text in-place, because you have to rewrite the entire rest of the contents of the file every time you add something new.
If the file is small enough to fit in memory, you can read it in, modify it, and write it back out. Otherwise, you really are better off with the temporary file.
I'm trying to create a new file and things don't seem to be working as I expect them too. Here's what I've tried:
File.new "out.txt"
File.open "out.txt"
File.new "out.txt","w"
File.open "out.txt","w"
According to everything I've read online all of those should work but every single one of them gives me this:
ERRNO::ENOENT: No such file or directory - out.txt
This happens from IRB as well as a Ruby script. What am I missing?
Use:
File.open("out.txt", [your-option-string]) {|f| f.write("write your stuff here") }
where your options are:
r - Read only. The file must exist.
w - Create an empty file for writing.
a - Append to a file.The file is created if it does not exist.
r+ - Open a file for update both reading and writing. The file must exist.
w+ - Create an empty file for both reading and writing.
a+ - Open a file for reading and appending. The file is created if it does not exist.
In your case, 'w' is preferable.
OR you could have:
out_file = File.new("out.txt", "w")
#...
out_file.puts("write your stuff here")
#...
out_file.close
Try
File.open("out.txt", "w") do |f|
f.write(data_you_want_to_write)
end
without using the
File.new "out.txt"
Try using "w+" as the write mode instead of just "w":
File.open("out.txt", "w+") { |file| file.write("boo!") }
OK, now I feel stupid. The first two definitely do not work but the second two do. Not sure how I convinced my self that I had tried them. Sorry for wasting everyone's time.
In case this helps anyone else, this can occur when you are trying to make a new file in a directory that does not exist.
If the objective is just to create a file, the most direct way I see is:
FileUtils.touch "foobar.txt"
The directory doesn't exist. Make sure it exists as open won't create those dirs for you.
I ran into this myself a while back.
File.new and File.open default to read mode ('r') as a safety mechanism, to avoid possibly overwriting a file. We have to explicitly tell Ruby to use write mode ('w' is the most common way) if we're going to output to the file.
If the text to be output is a string, rather than write:
File.open('foo.txt', 'w') { |fo| fo.puts "bar" }
or worse:
fo = File.open('foo.txt', 'w')
fo.puts "bar"
fo.close
Use the more succinct write:
File.write('foo.txt', 'bar')
write has modes allowed so we can use 'w', 'a', 'r+' if necessary.
open with a block is useful if you have to compute the output in an iterative loop and want to leave the file open as you do so. write is useful if you are going to output the content in one blast then close the file.
See the documentation for more information.
data = 'data you want inside the file'.
You can use File.write('name of file here', data)
You can also use constants instead of strings to specify the mode you want. The benefit is if you make a typo in a constant name, your program will raise an runtime exception.
The constants are File::RDONLY or File::WRONLY or File::CREAT. You can also combine them if you like.
Full description of file open modes on ruby-doc.org