> For the complete documentation index, see [llms.txt](https://certil-remy.gitbook.io/learn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://certil-remy.gitbook.io/learn/ruby/untitled-41.md).

# Using Hashes lab

## Objectives

1. Create hashes using the literal constructor.
2. Retrieve data from hashes using the bracket method.
3. Add data to hashes using the "bracket-equals" method.

## Instructions

### Challenge I: Instantiating Hashes

In the `my_hash` method, use the literal constructor to set a variable called `your_hash` equal to a hash with key/value pairs of your choice.

*Note: The variable name you use within the `my_hash` method does not actually matter. All that matters is that the return value of `my_hash` is a valid hash. The return values of a method is always the last line of code a method executes.*

Remember, key/value pairs are associative. It doesn't make sense to have a key/value pair of `"my_name" => 78`. It *does* make sense to have a key/value pair of `"my_name" => "Herman Melville"` (if you happen to be that author, of course).

### Challenge II: Hash with Data

In the `shipping_manifest` method, set a variable called `the_manifest` equal to a hash.

Fill that hash with key/value pairs that describe the following information and then return the hash:

| Inventory          | Quantity |
| ------------------ | -------- |
| whale bone corsets | 5        |
| porcelain vases    | 2        |
| oil paintings      | 3        |

Your hash should have the following key/value pairs:

```
"whale bone corsets" => 5
"porcelain vases" => 2
"oil paintings" => 3
```

### Challenge III: Retrieving Data

In the `retrieval` method we've given you the `shipping_manifest` hash that you built out in the previous challenge. Use the `[]` hash method to look up and return the value of the `"oil paintings"` key of the `shipping_manifest` hash.

For example, if we have the following hash:

```
hash = {"key1" => "value1"}
```

We can look up and return the value of `"key1"` like this:

### Challenge IV: Adding Data

In the `adding` method, we've once again given you the `shipping_manifest` hash. Use the `[]=` method to add the following data to the hash:

| Inventory  | Quantity |
| ---------- | -------- |
| muskets    | 2        |
| gun powder | 4        |

In the end your hash should have all of the following keys and values:

```
"whale bone corsets" => 5
"porcelain vases" => 2
"oil paintings" => 3
"muskets" => 2
"gun powder" => 4
```

This method must return the `shipping_manifest` hash. Make sure that the last line of the method is a reference to the variable `shipping_manifest`.

Remember that the return value of using the `[]=` method is the value of the key/value pair you added. We need our `adding` method to return the `shipping_manifest`. Here's a refresher on the `[]=` method:

```
hash = {"key1" => "value1"}
hash["key2"] = "value2"
#=> "value2"

hash
#=> {"key1" => "value1", "key2" => "value2"}
```

Hope you had fun hashing out the ship's inventory!

clone repo here: <https://github.com/learn-co-curriculum/my-first-hash>