multidimensional arrays arrays inside an array in ruby

You can use Ruby itself to figure out the answer to such questions:

sandwiches.map(&:length)
#=> [2, 2, 4, 1, 3]

This gives you the length of each array nested in sandwiches.

Note that .map(&:length) is the short version of .map { |x| x.length }.

The sandwiches array contains 5 elements (and each of these elements is also an array):

sandwiches = [
["cheese", "ham"], #first element of sandwiches -> an array with 2 elements (cheese and ham)
["avocado", "bacon"], #second element of sandwiches, an array with 2 elements (avocado and bacon)
["tomato","pesto","cheese","mayo"], # third element of sandwiches, an array with 4 elements (tomato, pesto, cheese and mayo)
["egg"], # fourth element of sandwiches, an array with one element (egg)
["turkey", "ketchup", "mustard"] # fifth element of sandwiches, an array with 3 elements (turkey, ketchup and mustard)
]

you have 1major array with 5 elements [0,1,2,3,4]

Element at position 0 is another array with 2 elements

Element at position 1 is another array with 2 elements too

Element at position 2 is another array with 4 elements

Element at position 3 is another array with 1 element

Element at position 4 is another array with 3 elements

Ps: u can consider a position each element separated by comas (,)

i.e: [ fisrt_element, second_element, [fist_element_of_this_arry, second_element_of_this_arry], fourth_element]

so the array above is one major array with 4 elements and element 3 is an array with two elements: [0,1, [ 0,1], 3]

remember that array position aways begin from 0