Re: 'Raw Expressions'
- To: mathgroup at smc.vnet.net
- Subject: [mg61654] Re: 'Raw Expressions'
- From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
- Date: Mon, 24 Oct 2005 21:07:12 -0400 (EDT)
- Organization: Uni Leipzig
- References: <djht17$sjt$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, what man N[] do ?? Regards Jens "Matt" <anonmous69 at netscape.net> schrieb im Newsbeitrag news:djht17$sjt$1 at smc.vnet.net... | Hello, | Given this as input: | | someArray = Array[r, {2, 2}, {2, 4}]; | Level[someArray, {-1}] | | which results in the following output: | | {2, 4, 2, 5, 3, 4, 3, 5} | | and the fact that a level specification of -1 is defined thusly: | "Level -1 contains all symbols and other objects that have no | subparts", | | one would naively expect that this: | | Apply[HeadNew, someArray, {-1}] | | would change all the integers in someArray to have new heads of | NewHead. However, on page 711 of Michael Trott's Programming | Guidebook, he states "The head of raw expressions does not get changed | by Apply." I assume that by 'raw expression' he means fundamental | types such as Integers, Reals, Strings, etc. This makes sense to me, | because it would be nonsensical to change the head of an integer to be | String or vice versa. However, a question did occur to me in the | hypothetical. Let's say that a function had been defined that had a | constraint upon a certain input, in that the input needed to be of | Integer type, but for some reason, I wanted to deal with the input | internally as a type of Real. How would I do that? | | Thanks, | | Matt |