how to concatenate multiple strings with commas if there is the same array data

I have the array data as drawn image description here

and I want to display data like this

0 = "16-11-1996 / IGD"
01 = "CBC", "DIFF"
04 = "GLUS "," UR "," CRE " 

I tried to use this PHP splitting arrays into groups based on equal values method but it was not what I expected.

i am just learning coding and i am not what way or what keywords should i use to find a solution. i hope someone can help me,

via Chebli Mohamed