Re: count the number of sub-list in a list
- To: mathgroup at smc.vnet.net
- Subject: [mg122243] Re: count the number of sub-list in a list
- From: Shizu <slivo.vitz at msa.hinet.net>
- Date: Sat, 22 Oct 2011 06:06:32 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
To find all the elements you need, use
Position[list, {{_, _, _}, {_, _, _}, {_, _, _}}]
So, you see the elements are all at level 2, since each element has 2 indices.
Count[list, _List, {2}] will give you the number of elements.
Or else, you would say,
Count[list, {{_, _, _}, {_, _, _}, {_, _, _}}, Infinity]
This also gives the result, but you don't need to know the position/level of your elements.
If you type TreeForm[list], you'll see the "shape" of your list. And figure out how to count them.