Problem with "starts_with?"

Ruby
1

How can I get this code to work in my classes?
http://api.rubyonrails.org/classes/ActiveSupport/CoreExtensions/String/StartsEndsWith.html

I’d like to have all my custom methods located in one file, which I can
just include

2

Skave R. [email protected] wrote:

How can I get this code to work in my classes?
http://api.rubyonrails.org/classes/ActiveSupport/CoreExtensions/String/
StartsEndsWith.html

require ‘rubygems’
require ‘activesupport’
include ActiveSupport::CoreExtensions::String

puts “howdy”.starts_with?(“ho”)

Is that the kind of thing you mean? m.

3

matt neuburg wrote:

Skave R. [email protected] wrote:

How can I get this code to work in my classes?
http://api.rubyonrails.org/classes/ActiveSupport/CoreExtensions/String/
StartsEndsWith.html

require ‘rubygems’
require ‘activesupport’
include ActiveSupport::CoreExtensions::String

puts “howdy”.starts_with?(“ho”)

Is that the kind of thing you mean? m.

hm, yea, but the problem is it’s not rails but simple ruby.
So I’d just like to add

def starts_with?(prefix)
prefix = prefix.to_s
self[0, prefix.length] == prefix
end

to my code where I can use it on all strings inside.

4

ah, I missed the “class String” part. works fine now, thanks

5

Skave R. wrote:
[snip]

So I’d just like to add

def starts_with?(prefix)
prefix = prefix.to_s
self[0, prefix.length] == prefix
end

to my code where I can use it on all strings inside.

Surely you just do it? (Or have I missed the point somehow?)

class String
def starts_with?(prefix)
prefix = prefix.to_s
self[0, prefix.length] == prefix
end
end

candidate = “Banana”
puts candidate.starts_with?(“Da”).to_s

Just make sure the first bit gets executed somewhere early on in your
application’s run.

HTH
John

6

Skave R. [email protected] wrote:

end

to my code where I can use it on all strings inside.

Ah - so you mean you want to implement starts_with? yourself. Sure,
then, as you’ve been shown, you can just implement a method on String.

However, please do note that my solution is “simple ruby”, not rails.
What I showed you is how I would do it. In other words, there is nothing
wrong with “stealing” existing code by requiring (and possibly
including) an existing module. I do this kind of thing all the time. For
example, I don’t use rails, but I do use the active support → string
core extensions quite a bit (esp. the unicode stuff). Why reinvent the
wheel? Sure, it happens that in your case it’s a very easy wheel to
reinvent; I’m just saying that snarfing up stuff from libraries into
your scripts isn’t something to run away from, it’s something to run
towards. It’s the Ruby way. m.