Re: new functional operator

*To*: mathgroup at smc.vnet.net*Subject*: [mg125645] Re: new functional operator*From*: Ray Koopman <koopman at sfu.ca>*Date*: Sun, 25 Mar 2012 00:15:20 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <jjfd6e$7u7$1@smc.vnet.net> <jjpakk$ov1$1@smc.vnet.net> <jkjrn9$43h$1@smc.vnet.net>

I vote for g /@ f /@ {1, 2, 3, 4} It's cleaner. On Mar 24, 12:05 am, DrMajorBob <btre... at austin.rr.com> wrote: > I'd still have to go with > > Composition[g, f] /@ {1, 2, 3, 4} > > It's fewer keystrokes and emphasizes that you're composing one function > with another, and it's not hard to the right to left convention we've > ALWAYS used in math. > > Bobby > > On Wed, 21 Mar 2012 17:53:12 -0500, Barrie Stokes > > <Barrie.Sto... at newcastle.edu.au> wrote: >> Hi Bobby >> >> I agree with your sentiments. The folk who like {1, 2, 3, 4} // f /@ # >> & // g /@ # & are those who regret the passing of assembly coding by >> hand, which opened up programming to the great unwashed. >> >> Of course it can be immeasurably improved by the addition of some more >> characters, to wit: >> >> {1, 2, 3, 4} // (f /@ # & ) // (g /@ # &) >> >> But, what about my favourite? >> >> Map[ (s \[Function] g[ f[ s ] ]), {1, 2, 3, 4} ] >> >> Or, somewhat less attractive IMHO, >> >> (s \[Function] g[ f[ s ] ]) /@ {1, 2, 3, 4}. >> >> I like (s \[Function] g[ f[ s ] ]) because to me it is intuitive, to >> use your word. I don't have to recall the way Composition[ ] works, I >> just have to know what g( f( x ) ) means in mathematics, and the >> \[Function] arrow is at least more suggestive to me of its >> meaning/effect than such as // or /@ or @@ or @@@, etc. I can at least >> suspect that \[Function] means "goes to" or "becomes". >> >> Barrie >> >> PS >> I've enjoyed this thread, MathGroup! >> >>>>> On 21/03/2012 at 9:46 pm, in message >>>>> <201203211046.FAA27... at smc.vnet.net>, >> DrMajorBob <btre... at austin.rr.com> wrote: >>> Here SIX several equivalent expressions from (IMHO) most intuitive or >>> readable to least: >>> >>> Composition[g, f] /@ {1, 2, 3, 4} >>> >>> {g[f[1]], g[f[2]], g[f[3]], g[f[4]]} >>> >>> g /@ f /@ {1, 2, 3, 4} >>> >>> {g[f[1]], g[f[2]], g[f[3]], g[f[4]]} >>> >>> Apply[Composition, {g, f}] /@ {1, 2, 3, 4} >>> >>> {g[f[1]], g[f[2]], g[f[3]], g[f[4]]} >>> >>> g@f@# & /@ {1, 2, 3, 4} >>> >>> {g[f[1]], g[f[2]], g[f[3]], g[f[4]]} >>> >>> Compose[g, f@#] & /@ {1, 2, 3, 4} >>> >>> {g[f[1]], g[f[2]], g[f[3]], g[f[4]]} >>> >>> {1, 2, 3, 4} // f /@ # & // g /@ # & >>> >>> {g[f[1]], g[f[2]], g[f[3]], g[f[4]]} >>> >>> The last is truly awful. >>> >>> Bobby >>> >>> On Tue, 20 Mar 2012 02:18:47 -0500, roby <roby.no... at gmail.com> wrote: >>> >>>>> That creates a information fog that makes *all* Mathematica code >>>>> harder >>>>> to understand, and Mathematica much harder to learn than it used to >>>>> be. >>>> >>>> {1, 2, 3, 4} /// f///g >>>> >>>>> {1, 2, 3, 4} // f /@ # & // g /@ # & >>>> >>>> sorry but I absolutly can't agree with your opinion in this case, the >>>> former expression is more or less fogless and would be much easier to >>>> understand. >>>> The latter expression bears a lot of clutter. > >>>> Robert > > -- > DrMajor... at yahoo.com