Re: Do-command

*To*: mathgroup at smc.vnet.net*Subject*: [mg102647] Re: [mg102588] Do-command*From*: Leonid Shifrin <lshifr at gmail.com>*Date*: Mon, 17 Aug 2009 04:31:46 -0400 (EDT)*References*: <200908161038.GAA01118@smc.vnet.net>

Hi Uwe, Do is not supposed to produce any output by itself (it produces Null). You should either use side effects (assignments) to save your results, or use a different programming style (such as functional programming). You can also use Reap and Sow. If I understand correctly what you really want, it can be achieved by In[1] = Map[Function[x, Select[{1, 2, 4, 7, 6, 2}, # >= x &]], Range[7]] Out[1] = {{1, 2, 4, 7, 6, 2}, {2, 4, 7, 6, 2}, {4, 7, 6}, {4, 7, 6}, {7, 6}, {7, 6}, {7}} With Reap and Sow, you will get it in this way: In[2] = Reap[Do[Sow[Select[{1, 2, 4, 7, 6, 2}, # >= i &]], {i, 7}]][[2, 1]] Out[2] = {{1, 2, 4, 7, 6, 2}, {2, 4, 7, 6, 2}, {4, 7, 6}, {4, 7, 6}, {7, 6}, {7, 6}, {7}} Regards, Leonid On Sun, Aug 16, 2009 at 2:38 PM, Uwe Gotzes <u.gotzes at googlemail.com> wrote: > Hi! > > Can anybody tell, why > Do[Select[{1, 2, 4, 7, 6, 2}, # >= i &], {i, 7}] > does not produce output in Mathematica? > >

**References**:**Do-command***From:*Uwe Gotzes <u.gotzes@googlemail.com>