Re: need something like ReplaceAllIndexed[]
- To: mathgroup at smc.vnet.net
- Subject: [mg108492] Re: need something like ReplaceAllIndexed[]
- From: Ray Koopman <koopman at sfu.ca>
- Date: Sat, 20 Mar 2010 02:44:51 -0500 (EST)
- References: <hnva5p$88b$1@smc.vnet.net> <hnvo2b$efu$1@smc.vnet.net>
On Mar 19, 4:44 am, Ray Koopman <koop... at sfu.ca> wrote:
> On Mar 19, 12:47 am, divisor <congruentialumina... at yahoo.com> wrote:
>> Hello mathGroup:
>>
>> I have an expression like this:
>>
>> b[ a[c], a[c], a[d]]
>>
>> a list like this:
>>
>> {e,f,g}
>>
>> I want to end up with
>>
>> b[ a[e], a[f], a[g]]
>>
>> I think of this as interleaving a list into an expression, but all my
>> tries with ./,.//,MapIndexed[],MapAt[], Partition[Riffle[]] have come
>> to no avail.
>>
>> Any help on this is greatly appreciated.
>>
>> Roger Williams
>> Franklin Laboratoryhttp://www.youtube.com/congruentlight
>
> In[1]:= b @@ a /@ {e,f,g}
>
> Out[1]= b[a[e],a[f],a[g]]
Sorry, I misunderstood (oversimplified) the question.
Here is the answer to a slightly more general question.
In[1]:= expr = b[ a[x], c[y], d[z] ];
list = {e, f, g};
Head[expr] @@ MapThread[Head[#1][#2]&,{List@@expr,list}]
Out[3]= b[ a[e], c[f], d[g] ]