Re: List of position-specifying functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg102363] Re: [mg102351] List of position-specifying functions*From*: Adriano Pascoletti <adriano.pascoletti at dimi.uniud.it>*Date*: Fri, 7 Aug 2009 05:28:04 -0400 (EDT)*References*: <200908061032.GAA01790@smc.vnet.net>

Something like this? In[7]:= (Function[x, x[[#1]]] & ) /@ plist Out[7]= {Function[x, x[[2]]], Function[x, x[[5]]], Function[x, x[[4]]], Function[x, x[[6]]], Function[x, x[[3]]]} Adriano Pascoletti 2009/8/6 Ray Koopman <koopman at sfu.ca> > I have a list of distinct positive integers, such as > > In[1]:= plist = {2, 5, 4, 6, 3}; > > I want to convert it to a list of position-specifying functions, > such as might be used as the second argument in SplitBy or GatherBy. > One way that works is: > > In[2]:= plist /. p_Integer->(#[[p]]&) > > Out[2]= { #1[[2]]&, #1[[5]]&, #1[[4]]&, #1[[6]]&, #1[[3]]& } > > I've been trying to get the same thing using Map, > but I haven't been able to do it. Any suggestions? > >

**References**:**List of position-specifying functions***From:*Ray Koopman <koopman@sfu.ca>