Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.

Topic: Is there any efficient easy way to compare two lists with the same length with Mathematica?
Replies: 7   Last Post: Jan 19, 2012 5:07 AM

 Messages: [ Previous | Next ]
 Murray Eisenberg Posts: 2,031 Registered: 12/6/04
Re: Is there any efficient easy way to compare two lists with the same length with Mathematica?
Posted: Jan 18, 2012 5:58 AM

Over time more and more things like this have been extended to work
automatically on lists. But so far, as you discovered, not GreaterEqual
(nor Greater, etc.). Here's one way without explicitly using Table:

a = RandomInteger[{0, 20}, 5];
b = RandomInteger[{0, 20}, 5];

The key there is MapThread, which does what you (and I) would evidently
like Mathematica to do automatically -- in effect, to make GreaterEqual
have Listable as an Attribute.

On 1/17/12 3:34 AM, Rex wrote:
> Given two lists `A={a1,a2,a3,...an}` and `B={b1,b2,b3,...bn}`, I would
> say `A>=B` if and only if all `ai>=bi`.
>
> There is a built-in logical comparison of two lists, `A==B`, but no
> `A>B`.
> Do we need to compare each element like this
>
> And@@Table[A[[i]]>=B[[i]],{i,n}]
>
> Any better tricks to do this?
>

--
Murray Eisenberg murray@math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower phone 413 549-1020 (H)
University of Massachusetts 413 545-2859 (W)
710 North Pleasant Street fax 413 545-1801
Amherst, MA 01003-9305

Date Subject Author
1/17/12 Rex
1/17/12 DrMajorBob
1/17/12 Bill Rowe
1/18/12 Murray Eisenberg
1/18/12 Andy Ross
1/18/12 James Stein
1/18/12 Alexei Boulbitch
1/19/12 DrMajorBob