Wolfram Mathematica

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11:01

Hi folks, I don't understand why the part operation at the end is not evaluated?

lst = 1 + x + x^2 + x^3;
pos = Position[lst, x]
lst @@ # & /@ pos

The output is as follows.

{(1 + x + x^2 + x^3)[2], (1 + x + x^2 + x^3)[3,
  1], (1 + x + x^2 + x^3)[4, 1]}

Rather what I want to obtain as follows:

{x,x,x}

Could you tell me the reason? I left my learning several years and I forgot almost everything. :-)

1 hour later…

anderstood

12:19

@MoneyOrientedProgrammer A free answer: maybe Part[lst, Sequence @@ #] & /@ pos?

Or lst[[Sequence @@ #]] & /@ pos

Money Oriented Programmer

13:01

Thank you. I already got the answer from @kglr :

lst[[##]]@@@pos

3 hours later…

rm -rf

15:46

@Mithical Ok. In any case, it wasn't an edit that added value to the post, so overriding it doesn't feel inappropriate.

1 hour later…

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17:40

@rm-rf note that the edit was immediately reapplied by J.M., I can’t tell from your answer whether you saw that or not. (Reapplying a change one doesn’t feel adds any value seems strange.)

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