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In the following application
f = MapThread[If [#2 == 0, 0, #1/#2] &, {d, c}] // N;
I need to overlay another mapping operation so that d and c can be taken from two other lists of which d and c are just two corresponding sublists. I tried
F=Map[MapThread[If [#2 == 0, 0, #1/#2] &, {#3, #4}]&,{D,C}]
Help would be much appreciated.
If your sublists are all the same length you can use the third parameter of MapThread:
dd = {{d11, d12, d13}, {d21, d22, d23}};
cc = {{c11, c12, c13}, {c21, c22, c23}};
MapThread[f, {dd, cc}, 2]
{{f[d11, c11], f[d12, c12], f[d13, c13]}, {f[d21, c21], f[d22, c22], f[d23, c23]}}
If they are not you can use a second MapThread:
dd = {{d11, d12, d13}, {d21, d22}};
cc = {{c11, c12, c13}, {c21, c22}};
MapThread[MapThread[f, {#, #2}] &, {dd, cc}]
{{f[d11, c11], f[d12, c12], f[d13, c13]}, {f[d21, c21], f[d22, c22]}}
Or my raggedMapThread from MapThread over sublists of different length
raggedMapThread[f, {dd, cc}, 2]
{{f[d11, c11], f[d12, c12], f[d13, c13]}, {f[d21, c21], f[d22, c22]}}
Or kglr's raggedThread (reproduced here in full since it's short)
raggedThread = Inner[Thread@*#, ##2, List] &;
raggedThread[f, dd, cc]
{{f[d11, c11], f[d12, c12], f[d13, c13]}, {f[d21, c21], f[d22, c22]}}
g[d_,c_]:=MapThread[If[#2==0,0,#1/#2]&,{d,c}]; f=MapThread[g,{dd,cc}]do what you want? That keeps one set of MapThread and #1,#2,& separated from the other. $\endgroup$fMapThread is going to take two lists of lists.fwill take one list from dd and one from cc. It will send those two lists tog.gwill take one item from each of the two lists and calculate your result. Tryg[d_,c_]:=MapThread[If[#2==0,0,#1/#2]&,{d,c}]; f=MapThread[g,{{{m,n},{o,p}},{{q,r},{s,t}}}]to see if the result is correct. If not then please provide an example input and what output should be. (D and C are functions defined by Mathematica and using those for variable names will cause problems) My method is only to put an inner Map or MapThread into a separate function. $\endgroup$ds come fromDandcs come fromCshouldn't yourMapbe anotherMapThread? $\endgroup$F=MapThread[MapThread[If[#2==0,0,#/#2]&,{##}]&,{cc,dd}]orF=MapThread[MapThread[If[#2==0,0,#/#2]&]@*List,{cc,dd}]do the trick? $\endgroup$