JSON Parser Acts Differently - ruby

I am trying to parse the following string called result:
{
"status":0,
"id":"faxxxxx-1",
"hypotheses":[
{"utterance":"skateboard","confidence":0.90466744},
{"utterance":"skate board"},
{"utterance":"skateboarding"},
{"utterance":"skateboards"},
{"utterance":"skate bored"}
]
}
Using obj = JSON.parse(result) in Ruby 1.8 with the json gem.
The command in question is:
puts "#{obj['hypotheses'][0]}"
My old workstation (whose harddrive died) gave me:
{"utterance" => "skateboard", "confidence" => 0.90466744}
My current workstation gives me:
confidence0.90466744utteranceskateboard
The old workstation was not set up by me, so I don't know what kind of packages were installed, while this current one was.
Why is there a difference in the output of the exact same script?
How can I make the current one look like the old one?
I am completely new to this btw.

In Ruby 1.8, Hash#to_s simply joins all of the elements together without spaces, equivalent to to_a.flatten.join('').
In Ruby 1.9, Hash#to_s is an alias to inspect and produces well-formatted output.
To get the equivalent thing in both cases:
puts obj['hypotheses'][0].inspect
The same thing applies to Array.

Related

Charlock_Holmes not returning anything in Ruby?

I'm trying to use the gem charlock_holmes (https://github.com/brianmario/charlock_holmes) to detect and correct character formatting errors. However, the program doesn't return anything.
My code is:
require 'charlock_holmes'
contents = File.read('./myfile.csv')
detection = CharlockHolmes::EncodingDetector.detect(contents)
# => {:encoding => 'UTF-8', :confidence => 100, :type => :text}
as specified in the documentation.
When I run this in the directory, I just get nothing at all:
user$ ruby detector.rb
user$
Expected behavior is that it returns the detected encoding (and, if desired, can change it as well). I've got all the gems installed, I think, and I've tried under both 1.9.2 and 2.0.0.
Any ideas what I'm doing wrong or how to find out? I'm afraid I'm new to ruby, but I have tried to do a pretty comprehensive search before asking and have come up blank.
I think you should put p detection in your file detector.rb.
Save your code as below :
require 'charlock_holmes'
contents = File.read('./myfile.csv')
detection = CharlockHolmes::EncodingDetector.detect(contents)
p detection
Now run it as you ran earlier.

A ruby script to run tail on a log file?

I want to write a ruby script that read from a config file that will have filenames, and then when I run the script it will take the tail of each file and output the console.
What's the best way to go about doing this?
Take a look at File::Tail gem.
You can invoke linux tail -number_of_lines file_name command from your ruby script and let it print on console or capture output and print it yourself (if you need to do something with these lines before you print it)
We have a configuration file that contain a list of the log files; for example, like this:
---
- C:\fe\logs\front_end.log
- C:\mt\logs\middle_tier.log
- C:\be\logs\back_end.log
The format of the configuration file is a yaml simple sequence , therefore suppose we named this file 'settings.yaml'
The ruby script that take the tail of each file and output the console could be like this:
require 'yaml'
require 'file-tail'
logs = YAML::load(File.open('settings.yaml'))
threads = []
logs.each do |the_log|
threads << Thread.new(the_log) { |log_filename|
File.open(log_filename) do |log|
log.extend(File::Tail)
log.interval = 10
log.backward(10)
log.tail { |line| p "#{File.basename(the_log,".log")} - #{line}" }
end
}
end
threads.each { |the_thread| the_thread.join }
Note: displaying each line I wanted to prefix it with the name of the file from which it originates, ...this for me is a good option but you can edit the script to change as you like ; is the same for the tails parameters.
if file-tail is missing in your environment, follow the link as #Mark Thomas posts in his answear; i.e you need to:
> gem install file-tail
I found the file-tail gem to be a bit buggy. I would write to a file and it would read the entire file again instead of just thelines appended. This happened even though I had log.backward set to 0. I ended up writing my own and figured that I would share it here in case any one else is looking for a Ruby alternative to the file-tail gem. You can find the repo here. It uses non_blocking io, so it will catch amendments to the file immediately. There is one caveat that can be easily fixed if you can program in the Ruby programming language; log.backward is hard coded to be -1.

Ruby Hash.has_key? returning false for the first key on Windows

I'm having a weird issue with Ruby hashes on windows. I'm loading the following YAML file and parsing it as a hash:
tasks:
- clone_skeleton, <skeleton_path>
- summit_capify, <skeleton_path>
I'm using YAML.load() to load the file into a hash. If I print out hash.keys tasks is listed as a key but if I do hash.has_key?("tasks") I get back false. However if I change the yaml to this
directory_structure:
tasks:
- clone_skeleton, <skeleton_path>
- summit_capify, <skeleton_path>
hash.has_key?("tasks") returns true but hash.has_key?("directory_structure") returns false. I haven't tested in Linux but I don't seem to be having this problem on OS X, just Windows. I'm using Ruby 1.9.2 and have tested in Cygwin and using the standard command prompt.
I don't know if this is a ruby bug, a problem with my YAML or something else. Any ideas?
UPDATE: Looks like this is fixed in Ruby 1.9.3
Is it possible the keys are Symbols and not Strings? Trying has_key?(:tasks).
Whenever you're debugging, don't do puts hash.keys, but do puts hash.keys.inspect - the latter indicates exactly what's going on.
Or you may want to do puts hash.inspect.

Why am I getting NoMethodError from IRB for my own Module and method

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

Unicode filenames on Windows in Ruby

I have a piece of code that looks like this:
Dir.new(path).each do |entry|
puts entry
end
The problem comes when I have a file named こんにちは世界.txt in the directory that I list.
On a Windows 7 machine I get the output:
???????.txt
From googling around, properly reading this filename on windows seems to be an impossible task. Any suggestions?
I had the same problem & just figured out how to get the entries of a directory in UTF-8 in Windows. The following worked for me (using Ruby 1.9.2p136):
opts = {}
opts[:encoding] = "UTF-8"
entries = Dir.entries(path, opts)
entries.each do |entry|
# example
stat = File::stat(entry)
puts "Size: " + String(stat.size)
end
You're out of luck with pure ruby (either 1.8 or 1.9.1) since it uses the ANSI versions of the Windows API.
It seems like Ruby 1.9.2 will support Unicode filenames on Windows. This bug report has 1.9.2 as target. According to this announcement Ruby 1.9.2 will be released at the end of July 2010.
If you really need it earlier you could try to use FindFirstFileW etc. directly via Win32API.new or win32-api.
My solution was to use Dir.glob instead of Dir.entries. But it only works with * parameter. It does not work when passing a path (c:/dir/*). Tested in 1.9.2p290 and 1.9.3p0 on Windows 7.
There are many other issues with unicode paths on Windows. It is still an open issue. The patches are currently targeted at Ruby 2.0, which is rumored to be released in 2013.

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