Re: Counting Elements in a List
- To: mathgroup at smc.vnet.net
- Subject: [mg27970] Re: Counting Elements in a List
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Tue, 27 Mar 2001 01:26:07 -0500 (EST)
- References: <99n61j$ihj@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
John: mylist = {{1, 2, 3, 4}, {1, 2, 3, 5}, {1, 3, 4, 6}, {1, 3, 6, 9}, {2, 4, 7,8}}; Count[mylist, x_/;x[[4]]>5] 3 -- Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565 "JOHN C ERB" <JOHN_C_ERB at prodigy.net> wrote in message news:99n61j$ihj at smc.vnet.net... > I have a list in which I want to count the number of times the 4th element > (i.e., 4th column) meets certain specifications (e.g., where it greater than > or equal to 8). > > I can do this by: > > mylist = {{1, 2, 3, 4}, {1, 2, 3, 5}, {1, 3, 4, 6}, {1, 3, 6, 9}, {2, 4, 7, > 8}}; > Length[Select[mylist, #[[4]] >= 8 &]] > > Surely, there is another, more direct, way of doing this using Count? > > > Thank you, > > John C. Erb > > email: John_C_Erb at prodigy.net > >