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I am loading a dataset into Mathematica and the format is always recognized as an Atom String:

DS[All, 4]

[1]: https://i.sstatic.net/VPX6d.png

AtomQ[DS[All, 4]]
(* True *)

In this format I cannot analyze the data. Unfortunately, I cannot modify the data before I load it into Mathematica.

Any help is welcome.

I tried ToString (horrible outcome):

In[111]:= ToString[DS[All, 4]]

Out[111]= "Dataset[{23,8, 24,9, 25,7, 23,8, 23,4, 23,8, 25,9, 24,4, \
24,9, 25,4, 25,3, 26,1, 25,5, 24,0, 23,9, 26,2, 24,6, 26,6, 26,4, \
26,2}, TypeSystem`Vector[TypeSystem`Atom[String], 20], <|Origin -> \
HoldComplete[Query[All, 4][Dataset`DatasetHandle[37310558245194]]], \
ID -> 52209799798783|>]"

and Replace

DS[All, 4] /. "," -> "."

but both did not work.

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  • 1
    $\begingroup$ Dataset objects are always atoms, so this part is not the issue. Unless you have more specific information (e.g. part of the file you're trying to import & the code you're using to do so), it will be very difficult to help you. $\endgroup$
    – Lukas Lang
    Commented Aug 15, 2019 at 12:56
  • $\begingroup$ So it is not possible to modify the data (in Atom form) once it it designated as a dataset? $\endgroup$
    – Philippe Dufour
    Commented Aug 15, 2019 at 13:06
  • $\begingroup$ you can modify them. Take a look at the (quite extensive) documentation of Dataset. If you tell us in more detail what you're after, we can point you in a more specific direction $\endgroup$
    – Lukas Lang
    Commented Aug 15, 2019 at 13:18
  • 2
    $\begingroup$ Can you show how you import the data? While it's possible to fix them afterwards, it might be significantly cleaner and faster to import it properly in the first place $\endgroup$
    – Lukas Lang
    Commented Aug 15, 2019 at 13:37
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    $\begingroup$ @PhilippeDufour - anytime you have something in the form of a Dataset, you can use Normal to convert it to a useful form. What do you see when you evaluate Normal[DS]? $\endgroup$
    – Jason B.
    Commented Aug 15, 2019 at 14:01

1 Answer 1

Reset to default
3
$\begingroup$ 
ds = Dataset[{"23,8", "24,9", "25,7", "23,8", "23,4", "23,8", "25,9", 
   "24,4", "24,9", "25,4", "25,3", "26,1", "25,5", "24,0", "23,9", 
   "26,2", "24,6", "26,6", "26,4", "26,2"}, 
  TypeSystem`Vector[TypeSystem`Atom[String], 20], <|
   Origin -> HoldComplete[
     Query[All, 4][Dataset`DatasetHandle[37310558245194]]], 
   ID -> 52209799798783|>];

ds2 = ds[Interpreter["Number", NumberPoint -> ","]]

enter image description here

Total[ds2]
(*  500.8  *)

Mean[ds2]
(*  25.04  *)

Probably the dataset could have been imported as a list of numbers instead of strings to begin with, but if not, then you can convert as above.

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2
  • $\begingroup$ Perfect, thanks a lot! That worked. $\endgroup$
    – Philippe Dufour
    Commented Aug 16, 2019 at 11:48
  • $\begingroup$ @PhilippeDufour You're welcome. $\endgroup$
    – Michael E2
    Commented Aug 16, 2019 at 13:15

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