I have this input:
Solve[x^2 + 3 x + 2 == 0, x] which gives this output:
{{x -> -2}, {x -> -1}} I want the first x to be named x1 and the second x to be named x2 without having to copy the value and doing x1=-2 manually and x2=-1
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3 Answers
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1 {x1, x2} = x /. Solve[x^2 + 3 x + 2 == 0, x] {-2, -1}
- $\begingroup$ loved it! Thanks! $\endgroup$Onizuka– Onizuka2014-09-19 17:43:05 +00:00Commented Sep 19, 2014 at 17:43
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2 {x1, x2} = Last @@@ Solve[x^2 + 3 x + 2 == 0, x] (* {-2, -1} *) or
{x1, x2} = Solve[x^2 + 3 x + 2 == 0, x][[All,1,-1]] (* {-2, -1} *) or
sol = Solve[x^2 + 3 x + 2 == 0, x]; sol[[All, 0]] = Last; {x1, x2} = sol (* {-2, -1} *) Note: Since this question has a much simpler structure than the question linked by Artes, these tricks work for the current case (with a single-variable expression to be solved), but not for the more general case in the linked Q/A.
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A certain generalization using an indexed variable:
r = FindInstance[Sin[x] == Cos[x] && -10 < x < 10, x, Reals, 15] // Values // Flatten // N {-5.49779, 7.06858, 0.785398, -8.63938, 3.92699, -2.35619}
Map[(x[#] = r[[#]]) &, Range @ Length @ r]; {x[1], x[2], x[3], x[4], x[5]} {-5.49779, 7.06858, 0.785398, -8.63938, 3.92699, -2.35619}
