That’s it. The * is called the splat operator. One caveat per @Mike Lewis (in the comments): “Be very careful with this. Ruby expands splats on the stack. If you do this with a large dataset, expect to blow out your stack.” So, for most general use cases this method is great, but use a … Read more
button_to like all others helpers for the views in Rails (e.g. link_to, form_for, image_tag…) simply converts your Rails command in HTML code. We could say that is a shortcut to write “pure HTML”. In your case, for button_to, you can see the reference (and what is printed) here: http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-button_to For example: I suggest you to … Read more
There’s no difference, in fact map is implemented in C as rb_ary_collect and enum_collect (eg. there is a difference between map on an array and on any other enum, but no difference between map and collect). Why do both map and collect exist in Ruby? The map function has many naming conventions in different languages. Wikipedia provides an overview: The map function originated in functional programming languages but is today supported (or may be … Read more
to_sym converts a string to a symbol. For example, “a”.to_sym becomes :a. It’s not specific to Rails; vanilla Ruby has it as well. It looks like in some versions of Ruby, a symbol could be converted to and from a Fixnum as well. But irb from Ruby 1.9.2-p0, from ruby-lang.org, doesn’t allow that unless you add your own to_sym method to Fixnum. I’m … Read more
Yes, it’s called next. This outputs the following:
In order: pid: The is the process ID (PID) of the process you call the Process.pid method in. ppid: The PID of the parent process (the process that spawned the current one). For example, if you run ruby test.rb in a bash shell, PPID in that process would be the PID of Bash. uid: The UNIX ID of the … Read more
Your item variable holds Array instance (in [hash_key, hash_value] format), so it doesn’t expect Symbol in [] method. This is how you could do it using Hash#each: or, without this:
This will iterate through all the elements: Prints: This will iterate through all the elements giving you the value and the index: Prints: I’m not quite sure from your question which one you are looking for.
It’s easy; just do the following: or And don’t forget to remove the script calls in the following files: ~/.bashrc ~/.bash_profile ~/.profile And maybe others depending on whatever shell you’re using.