How to loop through a nested array in liquid syntax

I am accessing the data from a json file from _data folder, I have this json data

{ 
   "content":[ 
      [ 
         "Unit I - Basic Principles of Electricity",
         "Introduction to basic principles of electricity - Classifications of materials - Basic "
      ],
      [ 
         "Unit II - Work, Power and Energy",
         "Work - Force - SI unit - Problem. Power, Energy - Electrical power - Electrical energy - "
      ]
   ]
}

An array holding two array’s withn the two array I have two array items. I try looping Like this And I dont get any output

{% for parentArr in page.content %} 

 {% for nestedArr in parentArr %} 
  {{nestedArr[0]}}
 {% endfor %} 

{% endfor %} 

Also I am using jekyll-datapage_gen plugin to create pages based on the json data in the _data folder. I would also like to add than I can access other values like page.title and page.objectives etc.

Check the Jekyll docs on how to access a _data file. The sample code you included below has you trying to loop over page.content which isn’t your data file.

Instead it should be site.data.filename with filename being the name of the .json file.