Re: Using "/@" Effectively

*To*: mathgroup at smc.vnet.net*Subject*: [mg104310] Re: Using "/@" Effectively*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Tue, 27 Oct 2009 04:58:43 -0500 (EST)*References*: <hc38lq$iae$1@smc.vnet.net>

You need to use Apply here instead of Map. To be precise, you need Apply on level 1 for which @@@ is the shorthand notation. So you would write: Sound[melody[#1, #2] & @@@ {{0, 1}, {5, 0.5}, {7, 0.5}, {12, 1}}, {0, 3}, SoundVolume -> .5] Actually, melody @@@ works as good as melody[#1, #2] & @@@ . Additionally, melody[p_Integer, d_Real] needs to rewritten as melody[p_Integer, d_?NumberQ] so that d can be both reals and integers. BTW In your examples you should try higher midi values to hear anything, or you should have a very good sound card. On my PC I need at least more than 50. Cheers -- Sjoerd On Oct 26, 6:30 am, BenT <brt... at pdmusic.org> wrote: > Given: > > $Version > "7.0 for Microsoft Windows (32-bit) (January 30, 2009)" > > miditofreq[n_Integer] := (440./64) 2^((n + 3)/12); > > and > > melody[p_Integer, d_Real] := > Play[Sin[miditofreq[p] 2 \[Pi] t], {t, 0, d}, SampleRate -> 44100, > SampleDepth -> 16] > > I want to be able to use a list of pitch and duration values for a > melody, and use it like the following, but cannot determine the method > to Map them properly, as in this (non-working) attempt: > > Sound[melody[#1, #2] & /@ {{0, 1}, {5, 0.5}, {7, 0.5}, {12, 1}}, {0, > 3}, SoundVolume -> .5] > > Can anyone show me the correct (or even a better) way to do so?