Re: Replace, test question

*To*: mathgroup at smc.vnet.net*Subject*: [mg120371] Re: Replace, test question*From*: PA32R <tio540s1 at gmail.com>*Date*: Wed, 20 Jul 2011 06:33:29 -0400 (EDT)*References*: <j0113e$qad$1@smc.vnet.net> <j03ora$adr$1@smc.vnet.net>

On Jul 19, 4:12 am, Yves Klett <yves.kl... at googlemail.com> wrote: > Hi, > > you need to supply x as argument to PrimeQ... alternatively use PatternTest: > > {58, 61, 15, 66, 10, 2, 24, 81, 45, 84} /. x_ /; PrimeQ[x] -> P > > {58, P, 15, 66, 10, P, 24, 81, 45, 84} > > {58, 61, 15, 66, 10, 2, 24, 81, 45, 84} /. x_?PrimeQ -> P > > {58, P, 15, 66, 10, P, 24, 81, 45, 84} > > Regards, > Yves > > Am 18.07.2011 12:15, schriebPA32R: > > > > > > > > > I'm very new to Mathematica and trying to work my way through it. I > > don't understand why: > > {58, 61, 15, 66, 10, 2, 24, 81, 45, 84} /. x_ /; PrimeQ -> P > > returns: > > {58, 61, 15, 66, 10, 2, 24, 81, 45, 84} > > > I would expect it to take the list, replace everything in the list > > that matches any pattern and passes the PrimeQ test, i.e., is prime, > > with P to yield: > > {58, P, 15, 66, 10, P, 14, 81, 45, 84} > > > Can someone explain my misunderstanding? > > > Thanks. Thanks everyone, I got it done. The assistance is much appreciated.