What does => mean?

Rails
1

I see => is a hash in ruby so is # , errrg But then I see in Rails
#=>
and then
render :action => ‘list.rhtml’

and other uses to it , I just need some sort of definition to what it
mean, is it redirect send_to ‘then’ no wait : is then , help…

2

trip dragon wrote:

I see => is a hash in ruby so is # , errrg But then I see in Rails
#=>
and then
render :action => ‘list.rhtml’

and other uses to it , I just need some sort of definition to what it
mean, is it redirect send_to ‘then’ no wait : is then , help…

When creating a hash, => is used to relate the keys to the values.

Anywhere you see =>, a hash is being created. Lots of Rails methods
take hashes as input.

Wes

3

Ah! many thanks! …

mhh note to self need more books… and need to make a real cheat sheet

4

Wes G. wrote:

trip dragon wrote:

I see => is a hash in ruby so is # , errrg But then I see in Rails
#=>
and then
render :action => ‘list.rhtml’

and other uses to it , I just need some sort of definition to what it
mean, is it redirect send_to ‘then’ no wait : is then , help…

When creating a hash, => is used to relate the keys to the values.

Anywhere you see =>, a hash is being created. Lots of Rails methods
take hashes as input.

Wes

Also you should know that hashes provided to method calls don’t always
need the {}'s around it to be a hash. For example, lets say I have a
method foo:

def foo(name, options = {})
puts “#{name} is #{options[:is]}”
end

Now as long the hash is the last element in the method arguments then
you can just string key/value pairs along as if they where individual
arguments:

foo(‘Sally’, :is => ‘hot’)

produces: Sally is hot

Which is exactly the same as:

foo(‘Sally’, {:is => ‘hot’})

So anytime you see a => remember its a hash and mentally put {}'s around
it. So in your example, render method excepts a hash.

render :action => ‘list.rhtml’

is the same as

render {:action => ‘list.rhtml’}

5

trip dragon wrote:

Ah! many thanks! …

mhh note to self need more books… and need to make a real cheat sheet

You need the following books:

Programming Ruby - Thomas (“pickaxe”)
Ruby for Rails - Black
Agile Web D. with Rails - Thomas, Heinemeier H. (2nd ed.)
[ optional: Rails Recipes - Fowler ]

plus a browser and a little patience, and you’ll be all set.

Good luck! It’s a lot of fun once you get into it.

Wes