Re: What is @@@?

*To*: mathgroup at smc.vnet.net*Subject*: [mg87203] Re: [mg87190] What is @@@?*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Fri, 4 Apr 2008 02:56:35 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200804031018.FAA26115@smc.vnet.net>*Reply-to*: murray at math.umass.edu

You'll find this in the tutorial "Input Syntax". -- tutorial/InputSyntax. (You can get to that from the main Documentation Center > Core Language > Syntax >tutorials. Or if in Mathematica 6.0.2 you open the built-in Virtual Book, then from Core Language > Appendix:Language Structure > Input Syntax > Types of Input Syntax.) On that tutorial page, search for @@@. You'll see that expr1 @@@ expr2 is a special input form that means Apply[expr1, expr2, {1}] So the effect is to replace heads in the parts of expr2 at level {1} by expr1. For example: Remove[f,g,a,b] Apply[f, g[List[1, 2], List[a, b]], {1}] g[f[1,2],f[a,b]] f@@@g[List[1,2],Lis[a,b]] (* same thing *) g[f[1,2],f[a,b]] More concrete example: Apply[Plus, {{1, 2}, {a, b}}, {1}] {3,a+b} Plus @@@ {{1, 2}, {a, b}} (* same thing *) {3,a+b} Contrast that with, e.g.: Plus @@ {{1, 2}, {a, b}} {1+a,2+b} that is, Apply[Plus,{{1,2},{a,b}}] (* same thing as preceding *) {1+a,2+b} Kevin J. McCann wrote: > I have seen several references to the command @@@ in this newsgroup, but > a query of the online Documentation Center just refers me to Apply (@@). > What does it do and where can I read about it? > > Thanks > > Kevin -- Murray Eisenberg murray at 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

**References**:**What is @@@?***From:*"Kevin J. McCann" <Kevin.McCann@umbc.edu>