conversion : procedure; specifies a procedure to be mapped onto the elements in the given column. This option is entered in the form conversion = procedure.

The SubsDatatype command changes the datatype of the entries in a given column of a DataFrame as well as the indicated datatype of the column.

Internally, the DataFrame/SubsDatatype command uses the DataSeries/SubsDatatype command to change the datatype.

If the conversion option is given, then the values in the DataSeries are converted by this conversion procedure. Otherwise, they are typically not modified, but there are exceptions. Internally, a new Array is constructed with the given datatype, and the current values are used to initialize this Array; this is the step where an automatic conversion could take place.

$\mathrm{genus}≔⟨''Rubus''\,''Vitis''\,''Fragaria''⟩\:$

$\mathrm{energy}≔⟨220\,288\,136⟩\:$

$\mathrm{carbohydrates}≔⟨11.94\,18.1\,7.68⟩\:$

$\mathrm{top\_producer}≔⟨\mathrm{Russia}\,\mathrm{China}\,\mathrm{USA}⟩\:$

$\mathrm{berries}≔\mathrm{DataFrame}\left(⟨\mathrm{energy}\left|\mathrm{carbohydrates}\right|\mathrm{top\_producer}|\mathrm{genus}⟩\,\mathrm{columns}=\left[\mathrm{Energy}\,\mathrm{Carbohydrates}\,\mathrm{`Top\; Producer`}\,\mathrm{Genus}\right]\,\mathrm{rows}=\left[\mathrm{Raspberry}\,\mathrm{Grape}\,\mathrm{Strawberry}\right]\,\mathrm{datatypes}=\left[\mathrm{integer}\,\mathrm{float}\,\mathrm{anything}\,\mathrm{string}\right]\right)$

$\mathrm{berries}≔\left[\begin{array}{ccccc}& \mathrm{Energy}& \mathrm{Carbohydrates}& \mathrm{Top\; Producer}& \mathrm{Genus}\\ \mathrm{Raspberry}& 220& 11.9400000000000& \mathrm{Russia}& ''Rubus''\\ \mathrm{Grape}& 288& 18.1000000000000& \mathrm{China}& ''Vitis''\\ \mathrm{Strawberry}& 136& 7.68000000000000& \mathrm{USA}& ''Fragaria''\end{array}\right]$

$\mathrm{Datatypes}\left(\mathrm{berries}\right)$

$\left[\mathrm{integer}\,{\mathrm{float}}_8\,\mathrm{anything}\,\mathrm{string}\right]$

$\mathrm{SubsDatatype}\left(\mathrm{berries}\,\mathrm{Energy}\,\mathrm{float}\right)$

$\left[\begin{array}{ccccc}& \mathrm{Energy}& \mathrm{Carbohydrates}& \mathrm{Top\; Producer}& \mathrm{Genus}\\ \mathrm{Raspberry}& 220.& 11.9400000000000& \mathrm{Russia}& ''Rubus''\\ \mathrm{Grape}& 288.& 18.1000000000000& \mathrm{China}& ''Vitis''\\ \mathrm{Strawberry}& 136.& 7.68000000000000& \mathrm{USA}& ''Fragaria''\end{array}\right]$

$\mathrm{berries}≔\mathrm{SubsDatatype}\left(\mathrm{berries}\,\mathrm{Energy}\,\mathrm{float}\right)$

$\mathrm{berries}≔\left[\begin{array}{ccccc}& \mathrm{Energy}& \mathrm{Carbohydrates}& \mathrm{Top\; Producer}& \mathrm{Genus}\\ \mathrm{Raspberry}& 220.& 11.9400000000000& \mathrm{Russia}& ''Rubus''\\ \mathrm{Grape}& 288.& 18.1000000000000& \mathrm{China}& ''Vitis''\\ \mathrm{Strawberry}& 136.& 7.68000000000000& \mathrm{USA}& ''Fragaria''\end{array}\right]$

$\mathrm{Datatype}\left(\mathrm{berries}\left[\mathrm{Energy}\right]\right)$

${\mathrm{float}}_8$

$\mathrm{berries}≔\mathrm{SubsDatatype}\left(\mathrm{berries}\,\mathrm{Genus}\,\mathrm{name}\,\mathrm{`=`}\left(\mathrm{conversion}\,x\mapsto \mathrm{convert}\left(x\,\mathrm{name}\right)\right)\right)$

$\mathrm{berries}≔\left[\begin{array}{ccccc}& \mathrm{Energy}& \mathrm{Carbohydrates}& \mathrm{Top\; Producer}& \mathrm{Genus}\\ \mathrm{Raspberry}& 220.& 11.9400000000000& \mathrm{Russia}& \mathrm{Rubus}\\ \mathrm{Grape}& 288.& 18.1000000000000& \mathrm{China}& \mathrm{Vitis}\\ \mathrm{Strawberry}& 136.& 7.68000000000000& \mathrm{USA}& \mathrm{Fragaria}\end{array}\right]$

$\mathrm{berries}≔\mathrm{SubsDatatype}\left(\mathrm{berries}\,\mathrm{`Top\; Producer`}\,\mathrm{string}\,\mathrm{`=`}\left(\mathrm{conversion}\,x\mapsto \mathrm{convert}\left(x\,\mathrm{string}\right)\right)\right)$

$\mathrm{berries}≔\left[\begin{array}{ccccc}& \mathrm{Energy}& \mathrm{Carbohydrates}& \mathrm{Top\; Producer}& \mathrm{Genus}\\ \mathrm{Raspberry}& 220.& 11.9400000000000& ''Russia''& \mathrm{Rubus}\\ \mathrm{Grape}& 288.& 18.1000000000000& ''China''& \mathrm{Vitis}\\ \mathrm{Strawberry}& 136.& 7.68000000000000& ''USA''& \mathrm{Fragaria}\end{array}\right]$

$\mathrm{Datatypes}\left(\mathrm{berries}\right)$

$\left[{\mathrm{float}}_8\,{\mathrm{float}}_8\,\mathrm{string}\,\mathrm{name}\right]$

The DataFrame/SubsDatatype command was introduced in Maple 2017.

For more information on Maple 2017 changes, see Updates in Maple 2017.