Question

I have a highly irregular nested list myList in mma, whenever I am given a integer sequence, such as 1,1,2,3,1 of any length, I want to know if

myList[[1,1,2,3,1]]

is valid; because if it is not, then I will get an error saying

Part::partw: part... does not exist

Thanks.

Answer 1

   Quiet[
       Check[mylist[[1, 1, 2, 3, 1]], Print[False], Part::partd], 
   Part::partd];  

You can replace Print[False] for any other action …

Edit

To check for both partd and partw messages the syntax is:

Quiet[Check[{{{1, 3}}, {2}}[[1, 4, 2, 3, 1]], 
    Print[False], {Part::partd, Part::partw}], 
   {Part::partd, Part::partw}];

HTH!