undefined method `symbolize_keys' after requiring active support. - ruby

I am trying to symbolize the keys of a hash in a non rails project. I can see the symbolize_keys method is part of Active Support so I imported the library but it still doesn't work.
Here is an example of it failing
2.4.2 :001 > require 'active_support'
=> true
2.4.2 :002 > {'test' => 'test'}.symbolize_keys
NoMethodError: undefined method `symbolize_keys' for {"test"=>"test"}:Hash
Expected output
{test: "test"}


You should require 'active_support/all' if you want active support core extensions also required:
2.3.4 :002 > require 'active_support/all'
=> true
2.3.4 :003 > {'test' => 'test'}.symbolize_keys
=> {:test=>"test"}

Related

IPSocket ruby NameError error?

When using IRB with input, getting error:
IPSocket.getaddress("localhost")
Error:
NameError: uninitialized constant IPSocket

Just add top before using the class :
require 'socket'
See this socket/ipsocket.c.
Example :-
2.1.0 :022 > require 'socket'
=> true
2.1.0 :023 > IPSocket.getaddress("localhost")
=> "::1"
2.1.0 :024 >

NoMethodError: undefined method `zone' for Time:Class

How do i use Time.zone in ruby if I am not using rails
I want to do Time.now but that's available in rails but not ruby
I thought that
require 'time'
would fix this and make it available in ruby but it didn't and I get
NoMethodError: undefined method `zone' for Time:Class

I don't know, what do you mean. But I think it should work as below :
(arup~>~)$ pry --simple-prompt
>> Time.now
=> 2014-04-09 23:19:04 +0530
>> Time.now.strftime('%Z')
=> "IST"
>> Time.now.strftime('%z')
=> "+0530"
>> Time.now.zone
=> "IST"
Documentation : #strftime and #zone .

You've tried to use zone as if it were a class method (Time.zone) [1]. If you want to use a class method:
1.9.3-p448 :007 > Time.now.zone
=> "EDT"
But Time.now is just a nice way of instantiating your own instance of Time[2]. So you're really just doing this (calling an instance method):
1.9.3-p448 :009 > time = Time.new
=> 2014-04-09 15:14:01 -0400
1.9.3-p448 :010 > time.zone
=> "EDT"
[1] http://www.railstips.org/blog/archives/2009/05/11/class-and-instance-methods-in-ruby/
[2] http://ruby-doc.org/core-1.9.3/Time.html#method-c-now

How do I test Digest::SHA2.hexdigest in online irb?

I want to see the hash created by the function Digest::SHA2.hexdigest. I do not have Ruby installed, so I went for the online irb. Typing
Digest::SH­A2.hexdige­st("hello"­)
gives
=> #<NameError: uninitialized constant Digest>
Is it possible to add the needed library in any online irb?

You need to do as below :
2.0.0-p0 :003 > require 'digest'
=> true
2.0.0-p0 :004 > Digest::SHA2.hexdigest("hello")
=> "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824"
2.0.0-p0 :005 >
So do first require 'digest'.
Try in tutorialspoint

Why is Ruby's Date class automatically loaded but DateTime is not?

Using IRB, why are the Date & Time classes automatically loaded, but DateTime is not? I have to require 'date', this does not make sense to me because I thought that both Date and DateTime were using the standard library 'date'?
ruby-1.9.2-p290 :001 > Date
=> Date
ruby-1.9.2-p290 :002 > Time
=> Time
ruby-1.9.2-p290 :003 > DateTime
NameError: uninitialized constant Object::DateTime
from (irb):3
from /Users/kamilski81/.rvm/rubies/ruby-1.9.2-p290/bin/irb:16:in `<main>'
ruby-1.9.2-p290 :004 > require 'date'
=> true
ruby-1.9.2-p290 :005 > require 'date'
=> false
ruby-1.9.2-p290 :006 > DateTime
=> DateTime

In IRB, include this line: require 'date' then you will be able to use DateTime.
irb(main):000:0> DateTime.class
NameError: uninitialized constant DateTime
from (irb):0
from /path/to/ruby/irb:12:in '(main)'
irb(main):001:0> require 'date'
=> true
irb(main):002:0> DateTime.class
=> Class

Worked for me when first initializing with require 'date'.

Being a little more curious, I tried:
$ ruby -e 'puts DateTime.class'
-e:1:in `<main>': uninitialized constant Object::DateTime (NameError)
[~, kamilski81#mac]
$ ruby -e 'puts Date.class'
-e:1:in `<main>': uninitialized constant Object::Date (NameError)
$ ruby -e 'puts Time.class'
Class
So it makes me think that it's an irb issue that automatically loads 'date'.

How do I use an ActionView::Helper in a Ruby script, outside of Rails?

I am looking to use ActionView::Helpers::NumberHelper from a Ruby script.
What all do I need to require etc.?

~> irb
ruby-1.9.2-p180 :001 > require 'action_view'
=> true
ruby-1.9.2-p180 :002 > ActionView::Base.new.number_to_currency 43
=> "$43.00"

As of Rails 3.2.13, you can do the following:
class MyClass
include ActionView::Helpers::NumberHelper
def my_method
...
number_with_precision(number, precision: 2)
...
end
end
You might need to require 'action_view' too.
Edit: This answer is still valid in Rails 4.2.3.

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