Community contributions, tips, and corrections to the documentation. (1708 notes)
If you are grouping similar records and paginating you might need to use :group You'll want to :select only the field you're collapsing on probably.
Model.count(:select => :attribute, :group => :attribute)
This will return an OrderedHash of your attributes with a count for each.
{"Column Con...
As is the case with the before_validation and before_save callbacks, returning false will break the callback chain. For example, the expire_cache_id method will not run if Rails.cache.expire returns false (as it will if the key is not cached with memcache).
=== Returning False Example (Bad)
a...
To get this access to this method you must:
require 'abbrev'
Before Rails 2.2 you could globally customize the default validation error messages by changing AR::Base.default_error_messages. The messages have now been moved to i18n, so to customize them in 2.2 and up, just create a +locales/+ folder in your +config/+ folder, copy +activerecord/lib/act...
Please note that this is an instance method, not a class method (which seemed more logical for me and took me a while to see what's wrong). So, you call it like this:
User.new.from_json '{"id": 1, "name": "DHH"}' # RIGHT!
not like this:
User.from_json '{"id": 1, "name": "DHH"}' # WRONG!
%a - The abbreviated weekday name (``Sun'')
%A - The full weekday name (``Sunday'')
%b - The abbreviated month name (``Jan'')
%B - The full month name (``January'')
%c - The preferred local date and time representation
%d - Day of the month (01..31)
%H - Hour of the day, 24-hour clock (...
%a - The abbreviated weekday name (``Sun'')
%A - The full weekday name (``Sunday'')
%b - The abbreviated month name (``Jan'')
%B - The full month name (``January'')
%c - The preferred local date and time representation
%d - Day of the month (01..31)
%H - Hour of the day, 24-hour clock (0...
A Follow-up to k776's note. If you want to specify tags or attributes, you should change your initializer to:
class String
def sanitize(options={})
ActionController::Base.helpers.sanitize(self, options)
end
end
Then you can call it from any string like so:
'string'.sanit...
If you're coming from Groovy/Grails: this is called an Expando in Groovy.
Case-insensitive
keywords.inject(text) { |text, keyword| text.gsub(/(#{keyword})/i, "<strong>\\\\1</strong>") }
can be replace by whatever HTML tag you want for hightlighting (, , ...)
such as XML, not only HTML as suggested in the text.
Usage example: cube = lambda {|x| x * x * x } cube.call(3) # => 27 cube.call(6) # => 216
Be careful if you use Time.now in views with time zone support enabled, as this will not actually do the time zone conversion.
Instead, use Time.zone.now.
You should use assert_in_delta when comparing floating-point numbers.
Using basic arithmetic you can get logarithm with any base:
def log_with_base base, num
Math.log(num) / Math.log(base)
end
Examples:
>> log_with_base 2, 10
=> 3.32192809488736
>> log_with_base 2, 2
=> 1.0
>> log_with_base 2, 4
=> 2.0
>> log_with_base 2, 16...
Using basic arithmetic you can get logarithm with any base:
def log_with_base base, num
Math.log(num) / Math.log(base)
end
Examples:
>> log_with_base 2, 10
=> 3.32192809488736
>> log_with_base 2, 2
=> 1.0
>> log_with_base 2, 4
=> 2.0
>> log_with_base 2, 16...
Em sua migration escreva da seguinte forma:
==== Exemplo de uso.
def self.up
change_column :sua_tabela, :seu_campo, :seu_tipo_campo
end
Into your migration write the follow:
==== Using Exemple
def self.up
change_column :yourtable, :your_field, :your_type_field
end
Please comment under the real method instead: find_index
The block usage was added in 1.8.7, so to get the same functionality in an earlier version of Ruby, you need to utilize the find method.
Here is a quick example:
match = list.find { |l| l.owner == myself }
match_index = list.index(match)
If you do some gymnastics, you can have it on one l...