Re: ReplaceAll applied to List

*To*: mathgroup at smc.vnet.net*Subject*: [mg72325] Re: ReplaceAll applied to List*From*: "dimitris" <dimmechan at yahoo.com>*Date*: Tue, 26 Dec 2006 05:58:37 -0500 (EST)*References*: <em8jdu$pel$1@smc.vnet.net>

Everything is normal. Look at the following example In[18]:= {2.3, 4, {7/8}, a, b, I, {{I^2}}} /. x_ /; NumberQ[x] -> x^2 Out[18]= {5.289999999999999, 16, {49/64}, a, b, -1, {{1}}} The rule is applied to all the levels of the expression. But In[19]:= Cases[{2.3, 4, {7/8}, a, b, I, {{I^2}}}, x_ /; NumberQ[x] -> x^2] Out[19]= {5.289999999999999, 16, -1} Only at level one here. Regards Dimitris Hannes Kessler wrote: > Hello, > > I want to apply transformation rules to those elements of a list which > are not lists themselves. The structure of the list is unknown in > advance. > > The following simple examples illustrate my my problems with ReplaceAll > and List: > > Expected result: > {1., {2}, 3} /. x_?NumericQ :> g > --> {g,{g},g} > > Unexpected result - inspite of AtomQ[{1., {2}, 3}] giving False > {1., {2}, 3} /. x_?AtomQ :> g > --> g[g, g[g], g] > > Similarly unexpected result - inspite of Not[ListQ[{1., {2}, 3}]] > giving False > {1., {2}, 3} /. x_?(Not[ListQ[#]] &) :> g > --> g[g, g[g], g] > > Any explanations for this behavior? > > Thanks in advance, > Hannes Kessler