Re: Something very simple.....

*To*: mathgroup at smc.vnet.net*Subject*: [mg87119] Re: [mg87103] Something very simple.....*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Tue, 1 Apr 2008 05:19:21 -0500 (EST)*References*: <200804010819.DAA11874@smc.vnet.net>

Just use Apply with level specification {1}: Apply[Sphere, sphlst, {1}] {Sphere[{5.11, 0.76, -0.32}, 100.39], Sphere[{7.18, -1.86, -8.19}, 98.02], Sphere[{26.71, -9.3, -6.85}, 111.27], Sphere[{0, 0, 0}, 100.], Sphere[{8.65, 4.28, -3.81}, 103.87]} Andrzej Kozlowski On 1 Apr 2008, at 10:19, Steve Gray wrote: > 1. I have a list of sphere centers and radii like this: > > sphlst={{{ 5.11, 0.76, -0.32}, 100.39}, > {{ 7.18, -1.86, -8.19}, 98.02}, > {{26.71, -9.30, -6.85}, 111.27}, > {{ 0, 0, 0}, 100.00}, > {{ 8.65, 4.28, -3.81}, 103.87}}. > > If I do Map[Sphere,sphlst] I get too many braces, like this: > > {Sphere[{{ 5.11, 0.76, -0.32}, 100.39}], > Sphere[{{ 7.18, -1.86, -8.19}, 98.02}], > Sphere[{{26.71, -9.30, -6.85}, 111.27}], > Sphere[{{ 0, 0, 0}, 100.00}], > Sphere[{{ 8.65, 4.28, -3.81}, 103.87}]} > > and Sphere needs for example Sphere[{1.11, 2.22, 3.33},4.5]. > What simple thing am I missing to remove the extra braces? > (I know I can use Table but isn't there a "one-step" method?) > Flatten doesn't seem to be useful here, or I'm using it wrong. > > 2. I have two lists, lsta={a,b,c,d,e,f} and lstb={1,3,4}. > I want the elements of lsta that do NOT correspond to elements > of lstb, in this case everything from lsta except elements > 1,3, and 4: result={b,e,f}. > (lstb won't have entries larger than Length[lsta]). > > Thanks for any tips. > > Steve Gray >

**References**:**Something very simple.....***From:*Steve Gray <stevebg@roadrunner.com>