YAML - Sequence Styles


To understand sequence styles, it is important to understand collections. The concept of collections and sequence styles work in parallel. The collection in YAML is represented with proper sequence styles. If you want to refer proper sequencing of tags, always refer to collections. Collections in YAML are indexed by sequential integers starting with zero as represented in arrays. The focus of sequence styles begins with collections.

Example

Let us consider the number of planets in universe as a sequence which can be created as a collection. The following code shows how to represent the sequence styles of planets in universe −

# Ordered sequence of nodes in YAML STRUCTURE
Block style: !!seq
- Mercury   # Rotates - no light/dark sides.
- Venus     # Deadliest. Aptly named.
- Earth     # Mostly dirt.
- Mars      # Seems empty.
- Jupiter   # The king.
- Saturn    # Pretty.
- Uranus    # Where the sun hardly shines.
- Neptune   # Boring. No rings.
- Pluto     # You call this a planet?
Flow style: !!seq [ Mercury, Venus, Earth, Mars,      # Rocks
                    Jupiter, Saturn, Uranus, Neptune, # Gas
                    Pluto ]                           # Overrated

Then, you can see the following output for ordered sequence in JSON format −

{
   "Flow style": [
      "Mercury", 
      "Venus", 
      "Earth", 
      "Mars", 
      "Jupiter", 
      "Saturn", 
      "Uranus", 
      "Neptune", 
      "Pluto"
   ], 
   
   "Block style": [
      "Mercury", 
      "Venus", 
      "Earth", 
      "Mars", 
      "Jupiter", 
      "Saturn", 
      "Uranus", 
      "Neptune", 
      "Pluto"
   ]
}
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