Re: Help with concatenating a list with &&
- To: mathgroup at smc.vnet.net
- Subject: [mg102197] Re: [mg102153] Help with concatenating a list with &&
- From: "David Park" <djmpark at comcast.net>
- Date: Sat, 1 Aug 2009 03:58:55 -0400 (EDT)
- References: <22188493.1249035660220.JavaMail.root@n11>
The documentation does seem to be confusing about that. "&&" apparently can only be used as an infix operator. But in your case you can just use plain "And". ls = {ex1, ex2, ex3, ex4}; And @@ ls ex1 && ex2 && ex3 && ex4 Apply[And, ls] ex1 && ex2 && ex3 && ex4 David Park djmpark at comcast.net http://home.comcast.net/~djmpark/ From: janey [mailto:janemkiwi at gmail.com] Can anyone help me make better use of mathematica's built in commands? My problem is to take the list of expressions ls: ls={ex1, ex2, ex3, ex4} and connect them to obtain ex1 && ex2 && ex3 && ex4 I thought I should be able to use && @@ ls or equivalently Apply[&&, ls] However this fails. I ended up using the very awkward conditions = ls[[1]] && ls[[2]] Do[conds = conds && ls[[i]], {i, 3, Length[ls]}] which works but feels like just bludgeoning the problem Does anyone know of a more elegant way to work this? Thanks, Jane.