Re: Counting number of numbers in a large list between two valus

*To*: mathgroup at smc.vnet.net*Subject*: [mg114523] Re: Counting number of numbers in a large list between two valus*From*: Fred Simons <f.h.simons at tue.nl>*Date*: Mon, 6 Dec 2010 06:14:54 -0500 (EST)

Op 6-12-2010 3:57, Lyle schreef: > Dear Listers, > > I have a large (5-20million) one dimensional list of real numbers and > I want to count the number of entries in the list that lie between 2 > specific values (x1, x2). I need to run the function for a number of > different ranges. > > ie. number of list entries (l), where x1<= l<= x2 > This seems to be a pretty fast solution: In[28]:= between[lst_, {x1_, x2_}] := Total[Unitize[Clip[lst, {x1, x2}, {0, 0}]]] In[29]:= lst = RandomReal[{-100, 100}, {10^7}]; between[lst, {-50, -40}] // Timing Out[30]= {0.125, 500249} Regards, Fred Simons Eindhoven University of Technology