cell2mat not working when cells are different lengths and what to find combinations

I want to obtain a matrix with all the player Vs player combinations. Whe i have my players names A, B, C and D the code below works perfectly. However whe i give my players names such as Alice, Ben, Cody and David the following code does not work. Is there something i can add to make it work?

function[changes] = calculating_changes(rating,position)
    changes = containers.Map;
    for player = keys(rating)
        changes(player{1}) = 0;
    end
    all_players=cell2mat(keys(rating))
%cell2mat converts the cell array to an ordinary array 
%puts the changes in a list with their corresponding player
    match_table = nchoosek(all_players,2)
%nchoosek is used to get a marix with all player vs player combinations
end

This code the output as followed when using ABCD I'd like it to do the same but with names not letters

all_players =

    'ABCD'
    
match_table =

  6×2 char array

    'AB'
    'AC'
    'AD'
    'BC'
    'BD'
    'CD'

Answer 1

[Shadaab Siddiqie]

Form my understanding you want to obtain a matrix with all the player Vs player combinations. But since player name might not be of same lenght, you can create a player Vs player cell array. This can be done by removing

all_players=cell2mat(keys(rating))

and replacing

match_table = nchoosek(all_players,2)

with

match_table = nchoosek(keys(rating),2)

If you want you can convert "match_table" to any format you like. Refere cell2mat and nchoosek for more information.