build a 3-dimensional array in sorted order using PHP ?

Question

Use below data and create a multi dimensional array in sorted
order. $array[continent][country][city].

Here's the content for your array:
City, Country, Continent; Tokyo, Japan, Asia;
Mexico City, Mexico, North America;
New York City, USA, North America;
Mumbai, India, Asia;
Seoul, Korea, Asia;
Shanghai, China, Asia;
Lagos, Nigeria, Africa;
Buenos Aires, Argentina, South America;
Cairo, Egypt, Africa;
London, UK, Europe.

Answer 1

Have you solved this case?
If not, can you share your code so I can see the problem?