Notes posted by metavida

RecordNotFound when any id not found

As an example of bansalakhil’s explanation.

User.find_by_id(1) #=> #<User:0x3d54a3c @attributes={"id"=>1}>
User.find_by_id(2) #=> #<User:0x3d519a4 @attributes={"id"=>2}>
User.find_by_id(3) #=> nil
User.find_by_id(1, 2) #=> an Array with 2 User instances
User.find_by_id(1, 3) #=> an ActiveRecord::RecordNotFound error

:confirm, :popup, and :method override :onclick

upplying any combination of :confirm, :popup, and/or :method options to the link_to method results the :onclick option being overridden.

Example:

link_to "Delete", '#', :confirm=>"Are you sure?", :onclick=>"destroyJsFunction()"
# expected output
# => <a href="#" onclick="if(confirm('Are you sure?')) {destroyJsFunction()}; return false;">Delete</a>
# actual output
# => <a href="#" onclick="return confirm('Are you sure?');">Delete</a>

Note that the actual output doesn’t include any mention of the “destroyJsFunction()” passed to the link_to method.

Rails 3 will use unobtrusive JavaScript, and I haven’t tested how that will interact with the :onclick option.

Looking for "to the power of"?

If you’re trying to calculate 2 to the power of 2, the ^ method is not what you want. Try ** instead.

2^2  #=> 0
2^8  #=> 10
2**2 #=> 4
2**8 #=> 256

File name without the extension

To get the file name without the extension you can use File.extname in combination with File.basename

File.basename("test.rb", File.extname("test.rb"))             #=> "test"
File.basename("a/b/d/test.rb", File.extname("a/b/d/test.rb")) #=> "test"
File.basename("test", File.extname("test"))                   #=> "test"
File.basename(".profile", File.extname(".profile"))           #=> ".profile"

For the file path use File.dirname

File.dirname provides what File.basename omits.

Wrapping peculiarities as of 2.x

In Rails 2.x word_wrap has been improved so that it no longer consumes multiple line-breaks or leading & trailing line-breaks.

word_wrap("\nOnce upon a time\n\nThe End\n")
# => \nOnce upon a time\n\nThe End

However it still doesn’t break long words

"supercalifragilisticexpialidocious".length
# => 30
word_wrap("\nOnce upon a supercalifragilisticexpialidocious time", 15)
# => \nOnce upon a\nsupercalifragilisticexpialidocious\ntime

Wrapping peculiarities

word_wrap will consume multiple line-breaks as well as leading & trailing line-breaks.

word_wrap("\nOnce upon a time\n\nThe End\n")
# => Once upon a time\nThe End

word_wrap will NOT break long words

"supercalifragilisticexpialidocious".length
# => 34
word_wrap("\nOnce upon a supercalifragilisticexpialidocious time", 15)
# => Once upon a\nsupercalifragilisticexpialidocious\ntime

If you want a function that will break long words & maintain multiple line-breaks try this alternative. Note it does add a line break at the end of the output.

def breaking_wrap_wrap(txt, col = 80)
  txt.gsub(/(.{1,#{col}})( +|$\n?)|(.{1,#{col}})/,
    "\\1\\3\n") 
end

breaking_wrap_wrap("\nOnce upon a supercalifragilisticexpialidocious time", 15)
# => \nOnce upon a\nsupercalifragil\nisticexpialidoc\nious time\n

Regex-based code from http://blog.macromates.com/2006/wrapping-text-with-regular-expressions/

print standard-looking messages during migration

Within a migration file you can use the say_with_time method to print out informational messages that match the style of standard migration messages. See the say method also.

say_with_time "migrate existing data" do
  # ... execute migration sql ...
end
#=> "-- migrate existing data"
#=> "   -> 0.0299s"

print standard-looking messages during migration

Within a migration file you can use the say method to print out informational messages that match the style of standard migration messages. The say_with_time method is also pretty great.

say "migrate existing data"
  #=> "-- migrate existing data"
# ... execute migration sql ...
say "updated all records", :subitem
  #=> "   -> updated 5 records"