Question: I am try to create a regular expression for a javascript project that covers every hyperlink that starts with "file://"

Thanks :)

Answer: 
In Ruby you must initialize a variable before using it (looks like a sound policy...). Note also that what you wrote is not idiomatic Ruby, an alternative:

```
months = {"Feb" => 0.upto(4).map { |i| "day#{i}" }}

```

To update:

```
months["Feb"] = 0.upto(4).map { |i| "day#{i}" }

```
Based on what you guys said I messed around and it looks like Ruby wants the key to exist before you can start assigning values to that key.

```
hashname = Hash.new
hashname[:foo] = {}
hashname[:foo][3] = "test"
hashname[:foo][1] = "test1"
hashname[:bar] = {}
hashname[:bar][3] = "test3"
puts hashname
puts hashname[:foo][1]

C:\Ruby>scratch.rb
{:foo=>{3=>"test", 1=>"test1"}, :bar=>{3=>"test3"}}
test1

```

Once the key exists, you can start assigning values as you please. Although in this case you can see that I am creating a "hash of hashes" instead of a "hash of arrays" as the .map method does which still eludes me as to why.

Thanks for the help!