Re: How can I make a sequence that includes lists?
- To: mathgroup at smc.vnet.net
- Subject: [mg125469] Re: How can I make a sequence that includes lists?
- From: "Oleksandr Rasputinov" <oleksandr_rasputinov at ymail.com>
- Date: Thu, 15 Mar 2012 00:26:26 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <jjpbbn$p9r$1@smc.vnet.net>
On Wed, 14 Mar 2012 05:46:31 -0000, JasonE <ebaughjason at gmail.com> wrote: > Hello folks, > > How can I make a sequence that includes lists? > Ex: > Sequence[apple, {rock, tree), {ocean, lake}] > > Here is my specific problem: > > I use this function to make associative arrays: > IndexedVariable[var_,indicesValues__]:=With[{dict=List[indicesValues]},Scan[(var[#[[1]]]=#[[2]])&,dict]] > > (I got it from: > http://www.physic.ut.ee/~kkannike/english/prog/mathematica/index.html#true_dict) > > > Here is an example of how it takes arguments: > IndexedVariable[f, {1, "a"}, {2, "b"}, {3, "c"}] > > In[2]:= f[1] > Out[2]= a > > In[3]:= f[2] > Out[3]= b > ect... > > You can imagine, some associations are too long to type out by hand. > Ex: {1, x1}, {2, x2}...{1000, x1000} > > When I make these associations programtically, I get a list back: > {{1, x1}, {2, x2},...{1000, x1000}} > > IndexedVariable[f,{{1, x1}, {2, x2}, {3, x3}...{1000, x1000}}] > does not work. > > It wants a sequence. > > > How can I make a sequence that includes lists? > > Thanks, > Jason > Just use IndexedVariable[f, Sequence @@ lst] or try IndexedVariable2[var_, lst_List] := ( MapThread[ (var[#1] = #2) &, Transpose[lst] ]; ); IndexedVariable2[var_, keys__] := IndexedVariable[var, {keys}]; which is both faster than IndexedVariable and accepts either lists or sequences of keys.