How to count how many objects there are in a list ?

M.E shared this question 4 years ago

Answered

I want to randomly extract an element from a list which holds elements with x in it.

I have tried the RandomElement commando, but it seems that it only works when it comes to extract numbers from a list.

Then I thought about using the ChooseElement commando and combine it with a Random commando. The ChooseElement commando works with elements with x in it. But then I have to know how many objects there are in the list which is a list with a random number of objects.

How can I get GeoGebra to count how many elements their are in a list ?

If this isn't possible, how can I else extract a random element from a list containing elements with x in it ?