Re: treatment on C[i]

*To*: mathgroup at smc.vnet.net*Subject*: [mg100322] Re: treatment on C[i]*From*: Szabolcs <szhorvat at gmail.com>*Date*: Mon, 1 Jun 2009 07:06:32 -0400 (EDT)*References*: <gvtmfq$get$1@smc.vnet.net>

On May 31, 1:34 pm, olfa <olfa.mra... at yahoo.fr> wrote: > Hi mathematica community, > C[i] is the default form for the i th parameter or constant generated > by mathematica in representing the results of various symbolic > computations in such functions as DSolve, RSolve and Reduce. > My question is: is it possible to know in advance how many C[i] will > be generated? > If not how to represent the generic form of them: For example I have > an input with reduce and mathematica generates in the output C[1],C > [2],C[3] and C[4] so four C[i] in the solutions but before that when I > wrote the input I did not know that it will generate four C[i] and I > need to use something in the input that represent C[i] in general > without knowing how many of them will be generated? I have tried to > use the pattern object _ like that C[ _ ] but it does not work. > You can always count them Count[C[1] + C[2]/x, C[_], {0, \[Infinity]}] or retrieve them Cases[C[1] + C[2]/x, C[_], {0, \[Infinity]}]