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Data Science Wolfram Language

How to add headers to a dataset?

Ehud Behar

Posted 5 months ago

Suppose I have the following dataset: dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}] How can I add a header `x` to the first column and a header `y` to the second column, so to get the following new dataset:? Dataset[{ <\|"x" -> 195, "y" -> 2.3\|>, <\|"x" -> 198, "y" -> 6.4\|>, <\|"x" -> 204, "y" -> -3.1\|> }] I am also looking for a command to assing units (cm and volts) to the values, so to get the following: Dataset[{ <\|"x" -> Quantity[195, "Centimeters"], "y" -> Quantity[2.3, "Volts"]\|>, <\|"x" -> Quantity[198, "Centimeters"], "y" -> Quantity[6.4, "Volts"]\|>, <\|"x" -> Quantity[204, "Centimeters"], "y" -> Quantity[-3.1, "Volts"]\|> }] Any ideas?

Suppose I have the following dataset:

dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}]

How can I add a header x to the first column and a header y to the second column, so to get the following new dataset:?

Dataset[{
  <|"x" -> 195, "y" -> 2.3|>,
  <|"x" -> 198, "y" -> 6.4|>,
  <|"x" -> 204, "y" -> -3.1|>
  }]

I am also looking for a command to assing units (cm and volts) to the values, so to get the following:

Dataset[{
  <|"x" -> Quantity[195, "Centimeters"], "y" -> Quantity[2.3, "Volts"]|>,
  <|"x" -> Quantity[198, "Centimeters"], "y" -> Quantity[6.4, "Volts"]|>,
  <|"x" -> Quantity[204, "Centimeters"], "y" -> Quantity[-3.1, "Volts"]|>
  }]

Any ideas?

POSTED BY: Ehud Behar

9 Replies

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Joshua Schrier

Joshua Schrier, Fordham University

Posted 5 months ago

Using a resource function... dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}]; ResourceFunction["DatasetWithHeaders"][ dataset, {"x", "y"}]

POSTED BY: Joshua Schrier

Vitaliy Kaurov

Vitaliy Kaurov, WOLFRAM Research

Posted 5 months ago

POSTED BY: Vitaliy Kaurov

Ehud Behar

Posted 5 months ago

Thanks very much. Regarding this instruction you wrote: dataset[All,Key["c"]/*<\|"ctotal"->Total,"clength"->Length\|>] Can you show me how to write it in a "FullForm" notatation, With explicit RightComposition? I am not so familiar with this infix shortcut and don't fully understand which expression is the argument of which function. Another question: You showed how to apply a function (`Total` and `Length`) on the values in each row. Suppose I want to add 3 to each value, or multiply each value by 2, in column `a`, how to do it?

POSTED BY: Ehud Behar

Hans Milton

Posted 5 months ago

For your second question, on adding units: dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}] Map[{Quantity[#[[1]],"Centimeters"],Quantity[#[[2]],"Volts"]}&,dataset//Normal]//Dataset

POSTED BY: Hans Milton

Eric Rimbey

Posted 5 months ago

Here's one way to start... dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}]; datasetWithHeader = dataset[All, Association @@ Thread[{"x", "y"} -> #] &] Then you could continue: datasetWithHeader[All, <\|"x" -> Quantity[#x, "Centimeters"], "y" -> Quantity[#y, "Volts"]\|> &]

Here's one way to start...

dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}];
datasetWithHeader = dataset[All, Association @@ Thread[{"x", "y"} -> #] &]

enter image description here

Then you could continue:

datasetWithHeader[All, <|"x" -> Quantity[#x, "Centimeters"], "y" -> Quantity[#y, "Volts"]|> &]

enter image description here

POSTED BY: Eric Rimbey

Ehud Behar

Posted 5 months ago

Very nice

POSTED BY: Ehud Behar

Eric Rimbey

Posted 5 months ago

Are you required to start with dataset = Dataset[{{195, 2.3}, {198, 6.4}, {204, -3.1}}] or do you have access to the raw data directly? E.g. data = {{195, 2.3}, {198, 6.4}, {204, -3.1}}