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.