#    
## Overview
Getting the keys of a hash at once in Ruby is possible using the **`keys` property**. It returns a new array that contains all the keys of a hash.


   // colors to use
    // red      #FD5E5E 
    // yellow   #FFDC5C 
    // green    #AFFE8B
    // blue     #33CFFF
    // purple   #CA99FF
    // grey     #C2C2C2

digraph g {
    splines = false;
    ranksep = 0.5;
    bgcolor = transparent;

    node[shape = record, fontname = "courier", fontsize="16"];
    // rankdir=LR
    

    matrix[label = <<table border="0" cellborder="1" cellspacing="0" > \
    <tr> \
        <td height="35" width="85" port="00" bgcolor="#C2C2C2">key</td> \
        <td height="35" width="85" port="01" bgcolor="#C2C2C2">value</td> \
    </tr> \
    <tr> \
        <td height="35" width="35" port="10" bgcolor="#CA99FF">one</td> \
        <td height="35" width="35" port="11" bgcolor="#33CFFF">1</td> \
        
    </tr> \
        <tr> \
        <td height="35" width="35" port="20" bgcolor="#CA99FF">two</td> \
        <td height="35" width="35" port="21" bgcolor="#33CFFF">2</td> \
      
    </tr> \
    <tr> \
        <td height="35" width="35" port="30" bgcolor="#CA99FF">three</td> \
        <td height="35" width="35" port="31" bgcolor="#33CFFF">3</td> \
        
    </tr> \

    </table>> shape=none];

   
  
}


## Syntax
```ruby
hash.keys
```
## Parameters
The `key` property does not take any arguments. 

## Return value
The value returned is an array containing all keys of the hash, `hash`.

## Code


# create some hashes
h1 = {one: 1, two: 2, three: 3}
h2 = {name: "okwudili", stack: "ruby"}
h3 = {"foo": 0, "bar": 1}
h4 = {M:"Mango", A: "Apple", B: "Banana"}

# get all keys of the hashes
# and print results
puts "#{h1.keys}"
puts "#{h2.keys}"
puts "#{h3.keys}"
puts "#{h4.keys}"

## Explanation
* **Lines 2-5**: We create four hashes.
* **Lines 9-12**: We use the `keys` property to get the keys of the hashes. We use the `puts` function to print the result.

How to get all hash keys at once in Ruby

Use `hash.keys` in Ruby to get an array of all hash keys.