I want to run ruby code in windows 10 platform. I have already installed ruby (rubyinstaller-devkit-2.4.5-1-x64) and tried to run on command prompt, but I got errors on my result. Previously it worked fine on terminal (MAC). Can someone help me on this? Thank you very much
Dir. for each ($path + "/input/") do |entry|
if entry.match(/.*osc$/)
fix_missing_logo(entry)
process(entry)
FileUtils.move $path + "/input/" + entry, $path + "/backup/"
end
error:
Traceback (most recent call last): convert.rb:332:in <main>':
undefined methodeach' for main:Object (NoMethodError)
That's not how Dir works. It should be calling each like this:
Dir.new($path + "/input/").each do |entry|
# ...
end
As a note, please try and stay away from global variables. In Ruby $ means global variable, it's not like PHP where that means just any old variable. Global variables cause all sorts of problems, like their origin and ownership being unclear, and of name collisions.
Related
I got a method where I use Dir.chdir(File.dirname(__FILE__)) inside. I am using it so that I can run the ruby file from anywhere and not get this error: No such file or directory # rb_sysopen - 'filename' (Errno::ENOENT).
Using the method for the first time works fine but using it for the second time throws an error. See method and exact error below.
def meth(string)
Dir.chdir(File.dirname(__FILE__))
hash = JSON.parse(File.read("file.json"))
# do something with hash and string
# return some value
end
meth("first string") # this returns what is expected
meth("second string") # this second usage of the method throws the error
Error sample pinpointing the line where I used Dir.chdir(File.dirname(__FILE__)):
dir/decoder.rb:44:in `chdir': No such file or directory # dir_s_chdir - lib (Errno::ENOENT)
Not sure if OS plays a role here, I am using an m1 BigSur on version 11.2.3.
Why is this happening?
What needs to be done so that the method` can be used as much as needed without running into the error?
Your problem here seems to be that __FILE__ is a relative path like dir/decoder.rb and that path becomes invalid after the first time Dir.chdir is used, because that command changes the working directory of your entire Ruby process. I think the solution would be to do something like this in your decoder.rb file:
DecoderDir = File.realpath(File.dirname(__FILE__))
def meth
Dir.chdir(DecoderDir)
# ...
end
I'm guessing that the first time the Ruby interpreter processes the file, that is early enough that the relative path in __FILE__ still refers to the right place. So, at that time, we generate an absolute path for future use.
By the way, a well-behaved library should not run Dir.chdir because it will affect all use of relative paths throughout your entire Ruby process. I pretty much only run Dir.chdir once and I run it near the beginning of my top-level script. If you're making a reusable library, you might want to do something like this to calculate the absolute path of the file you want to open:
DecoderJson = File.join(DecoderDir, 'file.json')
I have the following script in a file called foo.rb
def foo(msg)
msg
end
def bar
thing = 123
thing
end
debugger
p foo(:hai)
I run the program in debug mode, like so:
ruby --debug -r debug foo.rb
Notice I make sure the stdlib debug is loaded via -r and I also put the ruby environment into debug mode using --debug
So the first output I get is unexpected:
Debug.rb
Emacs support available.
/Users/M/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:57: RUBYGEMS_ACTIVATION_MONITOR.enter
After that, if I press c to 'continue' the program ends with the following error:
Exception `NameError' at foo.rb:10 - undefined local variable or method `debugger' for main:Object foo.rb:10:in `<main>': undefined local variable or method `debugger' for main:Object (NameError)
Can anyone tell me what I'm doing wrong, and how to actually get debug mode to recognise the relevant debugger command (if that's even the correct command to be using; the docs aren't clear at all on this)
Note: I'm not interested in using 3rd party gems in this instance (e.g. pry or ruby-debug). I'm only interested in understanding how to use the stdlib debugger that comes with Ruby
Update
Since this question was answered, I've gone ahead and created a gist for future reference. For anyone stumbling across this thread you might find it useful: https://gist.github.com/Integralist/5658cb218bb50494a1fa
Don't use -r. The entire mechanism by which an interactive debugging sessions is loaded is by the literal line of code require 'debug'.
Your code should look like this:
def foo(msg)
msg
end
def bar
thing = 123
thing
end
require 'debug'
p foo(:hai)
And you should run the program by simply typing ruby <program_name>.rb.
Doing the Ruby Koans, in the file about_symbols at line 88, I'm not sure of the answer.
This is the code:
def test_symbols_cannot_be_concatenated
# Exceptions will be pondered further farther down the path
assert_raise(what should i put?) do
:cats + :dogs
end
The point of the Ruby Koans is to learn by reading and trying things out.
Open up a terminal and start irb. Then try using the + operator on two symbols. Check the error you get and substitute it as appropriate in the Koans file.
Assuming that your prompt ends in $, that will look something like this:
$ irb
irb(main):001:0> :cats + :dogs
The answer you need will be clear pretty quickly in the error that irb spits out.
To go through step by step in case your completely new to Ruby you could try:
Open up a terminal
Type irb at your prompt to get to the interactive ruby prompt
This is where you can quickly try out different Ruby things
Type the command in question :cats + :dogs
Review the output which will look like
NoMethodError: undefined method `+' for :cats:Symbol
from (irb):1
The name of the exception thrown which is what you are looking for is the first thing e.g. NoMethodError
I have taken this example exactly from the Ruby Cookbook. Unfortunately for me, like a whole lot of the examples in that book, this one does not work:
my file (Find.rb - saved both locally and to Ruby\bin):
require 'find'
module Find
def match(*paths)
matched=[]
find(*paths) { |path| matched << path if yield path }
return matched
end
module_function :match
end
I try to call it this way from IRB, according to the example the book provides:
irb(main):002:0> require 'Find'
=> false
irb(main):003:0> Find.match("./") { |p| ext = p[-4...p.size]; ext && ext.downcase == "mp3" }
It SHOULD return a list of mp3 files in my recursive directory. Instead, it does this:
NoMethodError: undefined method `match' for Find:Module
from (irb):3
from C:/Ruby192/bin/irb:12:in `<main>'
What gives? I'm new at this (although I MUST say that I'm farther along with Python, and much better at it!).
How can I get IRB to use my method?
I ran into this with irb on a Mac running Snow Leopard while using the default version of ruby (and irb of course) installed with OS X. I was able to get past it by including the module in IRB after loading the module or in the file after the module definition.
include module_name
I'm not sure if this is a defect or known behavior.
The only explanation is that the code you posted is not the code you are running, since both carefully reading it and simply cut&paste&running it shows absolutely no problems whatsoever.
What directory are you calling IRB from? Try calling it from the directory where your find.rb file is located. Also, I don't know if it makes any difference but convention is to name the file the lowercase version of the module / class. So the module would be Find and the file name would be find.rb. You shouldn't need the require call in the file itself.
So, start your command prompt window, cd into the directory that contains find.rb and run irb. In IRB you should be able to require "find" and it should return true. From there you should be able to call Find.match.
I know this question is already 3 years old, but since this is the first hit on google for the problem, and I had been banging my head against the wall all afternoon with the same problem doing the tutorial here: http://ruby.learncodethehardway.org/book/ex25.html, here goes: the function definition in the module should read
module Find
def Find.match(*paths)
...
end
end
Hi I have been testing some very basic things in ruby and discover the following.
If i put in a file called xxxx.rb in this path "C:\Documents and Settings\Desktop\xxxx.rb"
puts __FILE__
and invoke this ruby file in a command line WITHOUT preceding ruby the output is the following
C:/Documents and Settings/Desktop/xxxx.rb
but if i invoke the xxxx.rb file with ruby (ruby xxxx.rb) in the command like the output is the following:
xxxx.rb
Why is that difference?? Thanks
PD: I'M ON WINDOWS XP SP3
RUBY VERSION: 1.8.6
What you want is to expand the path properly:
# Affected by the current working directory, etc.
puts __FILE__
# Always an absolute path
puts File.expand_path(__FILE__, Dir.getwd)
This takes your current working directory into account.
I'm guessing that when you just double click on the file, the absolute path gets passed. You should achieve the same effect by calling it like:
ruby C:/Documents and Settings/Desktop/xxxx.rb