Using |batch filter

The |batch filter divides a list into smaller sets. These sets can be specified to a size, incomplete sets can be filled with a default value, and original array keys can be preserved or not.

• automation
• output

• 
  start:
    set:
      items@json: [1,2,3,4,5,6,7,8,9,10]
    return:
      batches: {{items|batch(size=3, fill=-1, preserve_keys=false)|json_encode}}
  
  

• 
  __return:
    batches: '[[1,2,3],[4,5,6],[7,8,9],[10,-1,-1]]'