Re: ReplaceAll question
- To: mathgroup at smc.vnet.net
- Subject: [mg82534] Re: ReplaceAll question
- From: Peter Pein <petsie at dordos.net>
- Date: Wed, 24 Oct 2007 04:22:41 -0400 (EDT)
- References: <ffkf46$sh6$1@smc.vnet.net>
Yaroslav Bulatov schrieb:
> b = 3;
> Hold[a[[b]]] /. {b -> c}
>
> ReplaceAll has no effect, why? What is the recommended way of carrying
> out the replacement above?
>
>
the "b" in the rule is evaluated. Use HoldPattern:
In[1]:=
b = 3;
Hold[a[[b]]] /. {HoldPattern[b] -> c}
Out[2]= Hold[a[[c]]]
Peter