Items tagged with member


I have a list


I want to be able to tell what position the element [3,5] is in the list

I'm using


is there anything faster

maybe instead of storing as a list, I can use rtables or something?

thankyou for your time

Eight matrices inside the list J:

J := [Matrix([[1, 0], [0, 1]]), Matrix([[0, -I], [-I, 0]]), Matrix([[0, -1], [1, 0]]), Matrix([[-I, 0], [0, I]]), Matrix([[-1, 0], [0, -1]]), Matrix([[0, I], [I, 0]]), Matrix([[0, 1], [-1, 0]]), Matrix([[I, 0], [0, -I]])];


Function member identifies J[2] as a member of J and returns its position in j:

member(J[2], J, 'j'); j;


Matrix multiplication inside a loop does not have a matrix type:

for i to 1 do for j to 2 do a := J[i].J[j]; member(a, J, 'k'); print(i, j, k, a, whattype(a)) end do end do;

Has anyone any ideia of what is going on?


The member function can provide the position of x in table/list s for the first variable




will provide p=1


If I would like to know the position of all a, [1,4,5], is there any simple way to obtain them? I can do something like



for i from 1 to 5 do

 if f[i]='a' then



 end if;

end do;


something like that

Thank you very much

I know how we can add a member to a mathematical set ,for example :

C := NULL;

C := C, V, B, X;


V, B, X

but, my problem is that how we can subtract a member from the defined set ?





Page 1 of 1