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Grouping the first two elements in a list of ordered triples


I have a long list of the form


{{0.005, 1.05, 1.*10^-20}, {0.015, 1.05, 1.*10^-20}, {0.025, 1.05, 
1.*10^-20}, {0.035, 1.05, 1.*10^-20}, {0.045, 1.05,
1.*10^-20}, {0.055, 1.05, 1.*10^-20}, {0.065, 1.05,
1.*10^-20}, ........, {3.505, -0.95, 1.*10^-20}}


The first two elements in each list item are coordinates, the third is a function value at those coordinates. I want to do an interpolation so that I can get the function value also at points in between the given coordinates. For that I need to reorder the list into the form


{{{0.005, 1.05}, 1.*10^-20}, {{0.015, 1.05}, 
1.*10^-20}, {{0.025, 1.05}, 1.*10^-20}, {{0.035, 1.05},
1.*10^-20}, {{0.045, 1.05}, 1.*10^-20}, {{0.055, 1.05},
1.*10^-20}, {{0.065, 1.05}, 1.*10^-20},.......

so that the coordinates are always grouped together. How do I do this best in Mathematica?



Answer



This is to summarize the methods given in the comments.


march



{{#1, #2}, #3} & @@@ list

{#[[1 ;; 2]], #[[3]]} & /@ list

mgamer


list /. {x_, y_, z_} -> {{x, y}, z}

eldo


Transpose[{list[[All, 1 ;; 2]], list[[All, 3]]}]


LLlAMnYP


{Most @ #, Last @ #}& /@ list

Through@*{Most, Last} /@ list

Through[{Most, Last}[#]] & /@ list

m_goldberg


Thread[{list[[All, {1, 2}]], list[[All, 3]]}]


TakeDrop[#, 2]& /@ list

$\qquad$ TakeDrop is better than Thread because it scans the list only once.


JasonB:


(* Don't bother reframing the list*)
Interpolation[list]
(* works just fine when list={{x1,y1,f[x1,y1]},{x2,y2,f[x2,y2]}...} *)

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