Broken free weekly Rails (e)

1. Public protected private

With no arguments, sets the default visibility for subsequently defined methods to public . With arguments, sets the named methods to have public visibility.

Many things in Ruby is just method!

2. System

Executes cmd in a subshell, returning true if the command was found and ran successfully, false otherwise. An error status is available in $?. The arguments are processed in the same way as for Kernel:: exec.

system("echo *")
system("echo", "*")  # echo "*"

produces:

config.h main.rb

*

3. `

Returns the standard output of running cmd in a subshell. The built-in syntax% x (...) uses this method. Sets $? To the process status.

`date` #=> "Wed Apr 9 08:56:30 CDT 2003\n"

`ls testdir`.split[1] #=> "main.rb"

`echo oops && exit 99` #=> "oops\n"

$?.exitstatus #=> 99

4. Reload

Reloads the attributes of this object from the database. The optional options argument is passed to find when reloading so you may do eg record.reload (: lock => true) to reload the same record with an exclusive row lock.

When do you need to do reload? When you hold a object whose state may be changed by others.

5. Render: partial => 'shared / search', locals => (: objects => ...)

Why do we need locals? Partial is designed for reuse, so, you donot have to have the same name instance variable in your action, and locals make the reuse possible.

分类:Ruby 时间:2009-07-14 人气:322
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