Re: Re: Programming style: postfix/prefix vs. functional
- To: mathgroup at smc.vnet.net
- Subject: [mg70647] Re: [mg70633] Re: [mg70587] Programming style: postfix/prefix vs. functional
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Sun, 22 Oct 2006 01:19:24 -0400 (EDT)
- References: <200610200921.FAA11092@smc.vnet.net> <200610210914.FAA29189@smc.vnet.net> <2A8E209D-C4D9-45C1-933B-5E3D955D99C5@mimuw.edu.pl> <acbec1a40610210543k3a861eb7tb3bdb777170618b@mail.gmail.com>
Well, I would say that f@x is just a "shorthand" for f[x] and does not "correspond" to any function. It seems to me that same applies to @@ and to @@@ and none of these cases ? will yield any information. In fact, ? itself works in a curious way. Sometimes it corresponds to the function Information; as in Information[Sin] which is the same as ?Sin. But in some cases, notably ?@ you can't use Information; this Information[@] does not parse correctly (I think this is the right way to use "parse" ;-)), in other words, it is not syntactically correct. So ? seems actually work in two different ways: as another way to input Information but also rather like the symbol ! in front of a file name, which displays the contents of the file on the screen and does not correspond to any Mathematica function. Andrzej Kozlowski On 21 Oct 2006, at 21:43, Chris Chiasson wrote: > Andrzej Kozlowski, > > Thanks for the wildcard info! > > So, does @ correspond to Operate? I think Operate is a bit different > than @, but I am not sure. > > On 10/21/06, Andrzej Kozlowski <akoz at mimuw.edu.pl> wrote: >> (tm) Pro* >> >> On 21 Oct 2006, at 18:14, Chris Chiasson wrote: >> >> > One thing I have wondered is, what function corresponds to the >> short >> > hand "@". I know @ appears in Operate. Also, the ? can sometimes >> tell >> > what function an operator represents (try ?/@ ) , but ?@ only gives >> > System`$ (the symbol $ in the context System). >> >> That's because the symbol @ already has another meaning as a "wild >> card": >> >> @ , one or more characters excluding upper$B!>(Bcase letters >> >> (A more general wild card is, of course *). So ?@ returns all the >> symbols defined in the contexts of the current session that do not >> contain capital letters. Evaluate some symbols whose names contain >> only small letter in Mathematica and try ?@ again to see this in >> action. >> >> Andrzej Kozlowski >> >> >> > >> > >> > On 10/20/06, Will Robertson <wspr81 at gmail.com> wrote: >> >> Hello, >> >> >> >> As a newcomer to Mathematica, I'm a little unsure on what "good >> >> style" >> >> would be in this programming language. I notice that several >> >> functions >> >> have prefix and postfix notations such as //. for >> ReplaceRepeated, /@ >> >> for Map, and so on. >> >> >> >> Clearly using these forms makes the code more compact, but >> sacrifices >> >> some level of readability. Are there guidelines or suggestions >> that >> >> have built up over the years of whether these are "good" or >> "bad" to >> >> use? >> >> >> >> If it's simply personal preference, what do you like to use? >> >> -- >> >> Many thanks, >> >> Will Robertson >> >> >> >> >> > >> > >> > -- >> > http://chris.chiasson.name/ >> > >> >> > > > -- > http://chris.chiasson.name/
- References:
- Programming style: postfix/prefix vs. functional
- From: "Will Robertson" <wspr81@gmail.com>
- Re: Programming style: postfix/prefix vs. functional
- From: "Chris Chiasson" <chris@chiasson.name>
- Programming style: postfix/prefix vs. functional