Re: Question about Tally on a list of lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg99356] Re: Question about Tally on a list of lists*From*: bleeckerj <bleeckerj at gmail.com>*Date*: Sun, 3 May 2009 05:24:44 -0400 (EDT)*References*: <gth5lg$f3m$1@smc.vnet.net>

On May 2, 3:01 am, Bill Rowe <readn... at sbcglobal.net> wrote: > On 5/1/09 at 5:23 AM, bleeck... at gmail.com (bleeckerj) wrote: > > >Alternatively, I'd even be happy to somehow reduce the precision of > >the numbers in the list, but after a few hours . I have not been > >able to figure out how to coax Mathematica to somehow truncate the > >numbers down to, say, 4 digits after the decimal point. This would > >create a kind of artificial Bin'ing of the data, which would be fine > >for my purposes. Removing the accuracy would allow me to effectively > >turn the data into a checkerboard of "hits." > > Truncation to 4 digits after the decimal point can be > accomplished using Floor. For example, > > In[7]:= x = RandomReal[] > > Out[7]= 0.623211 > > In[8]:= Floor[x, .0001] > > Out[8]= 0.6232 > > Here, I have assume a positive value and taken your "truncation" > literally. For negative values, you would need to use Ceiling > instead of Floor to achieve the same truncation. Quite possibly > it would be better to use Round in place of Floor. For example, > > In[10]:= x = RandomReal[] > > Out[10]= 0.713353 > > In[11]:= Round[x, .0001] > > Out[11]= 0.7134 Thanks for the tip Bill! Sorry for the obvious question =96 I'm still getting used to Mathematica's idioms... Julian