The Reference command creates a reference to a data set and retrieves metadata about the data available for the data set. It returns a Reference object.

The corresponding data can then be retrieved by converting the object to a suitable data structure. The data structures supported differ from reference to reference, but Matrix is always supported.

For more information, see the Reference object help pages for data coming from particular data sources (for example, Quandl or Builtin).

$\mathrm{with}\left(\mathrm{DataSets}\right)\:$

$\mathrm{qdata}≔\mathrm{Reference}\left(''Quandl''\,''FRED/CANPOPL''\right)$

$\mathrm{qdata}≔\left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Population\; in\; Canada\; (DISCONTINUED)}\\ \mathrm{Quandl\; FRED/CANPOPL}\\ \mathrm{up\; to\; 52\; rows\; (annual),\; 1\; column}\\ \mathrm{1960-01-01\; -\; 2011-01-01}\end{array}\right]$

$\mathrm{bdata}≔\mathrm{Reference}\left(''Builtin''\,''Country''\right)$

$\mathrm{bdata}≔\left[\begin{array}{ccccc}\mathrm{Country\; (Name)}& \mathrm{CO2\; Emissions}& \mathrm{CPI\; Change}& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{\dots }\right]\right)& \mathrm{(124\; more)}\\ \mathrm{Afghanistan}& \mathrm{TimeSeries\; 9809.225}& \mathrm{TimeSeries\; 4.9759515055383}& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{\dots }\right]\right)& \\ \mathrm{Albania}& \mathrm{TimeSeries\; 5716.853}& \mathrm{TimeSeries\; 1.41109078954244}& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{\dots }\right]\right)& \\ \mathrm{Algeria}& \mathrm{TimeSeries\; 145400.217}& \mathrm{TimeSeries\; 1.95176821052894}& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{\dots }\right]\right)& \\ \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{⋮}\right]\right)& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{⋮}\right]\right)& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{⋮}\right]\right)& \mathrm{Typesetting}:-\mathrm{\_Hold}\left(\left[\mathrm{\ddots }\right]\right)& \\ \mathrm{(182\; more)}& & & & \end{array}\right]$

$\mathrm{convert}\left(\mathrm{qdata}\,\'\mathrm{Matrix}\'\right)$

$\mathrm{convert}\left({\mathrm{bdata}}_{1..3\,1..3}\,\'\mathrm{Matrix}\'\right)$

$\left[\begin{array}{cccc}''Afghanistan''& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{CO2\; emissions\; (kt)\; -\; Afghanistan}\\ \mathrm{Quandl\; WWDI/AFG\_EN\_ATM\_CO2E\_KT}\\ \mathrm{up\; to\; 65\; rows\; (annual),\; 1\; column}\\ \mathrm{1950-12-31\; -\; 2014-12-31}\end{array}\right]& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Inflation,\; consumer\; prices\; (annual\; \%)\; -\; Afghanistan}\\ \mathrm{Quandl\; WWDI/AFG\_FP\_CPI\_TOTL\_ZG}\\ \mathrm{up\; to\; 13\; rows\; (annual),\; 1\; column}\\ \mathrm{2005-12-31\; -\; 2017-12-31}\end{array}\right]& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Mortality\; rate,\; under-5\; (per\; 1,000\; live\; births)\; -\; Afghanistan}\\ \mathrm{Quandl\; WWDI/AFG\_SH\_DYN\_MORT}\\ \mathrm{up\; to\; 59\; rows\; (annual),\; 1\; column}\\ \mathrm{1960-12-31\; -\; 2018-12-31}\end{array}\right]\\ ''Albania''& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{CO2\; emissions\; (kt)\; -\; Albania}\\ \mathrm{Quandl\; WWDI/ALB\_EN\_ATM\_CO2E\_KT}\\ \mathrm{up\; to\; 65\; rows\; (annual),\; 1\; column}\\ \mathrm{1950-12-31\; -\; 2014-12-31}\end{array}\right]& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Inflation,\; consumer\; prices\; (annual\; \%)\; -\; Albania}\\ \mathrm{Quandl\; WWDI/ALB\_FP\_CPI\_TOTL\_ZG}\\ \mathrm{up\; to\; 28\; rows\; (annual),\; 1\; column}\\ \mathrm{1992-12-31\; -\; 2019-12-31}\end{array}\right]& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Mortality\; rate,\; under-5\; (per\; 1,000\; live\; births)\; -\; Albania}\\ \mathrm{Quandl\; WWDI/ALB\_SH\_DYN\_MORT}\\ \mathrm{up\; to\; 41\; rows\; (annual),\; 1\; column}\\ \mathrm{1978-12-31\; -\; 2018-12-31}\end{array}\right]\\ ''Algeria''& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{CO2\; emissions\; (kt)\; -\; Algeria}\\ \mathrm{Quandl\; WWDI/DZA\_EN\_ATM\_CO2E\_KT}\\ \mathrm{up\; to\; 65\; rows\; (annual),\; 1\; column}\\ \mathrm{1950-12-31\; -\; 2014-12-31}\end{array}\right]& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Inflation,\; consumer\; prices\; (annual\; \%)\; -\; Algeria}\\ \mathrm{Quandl\; WWDI/DZA\_FP\_CPI\_TOTL\_ZG}\\ \mathrm{up\; to\; 50\; rows\; (annual),\; 1\; column}\\ \mathrm{1970-12-31\; -\; 2019-12-31}\end{array}\right]& \left[\begin{array}{c}\mathrm{Data\; set}\\ \mathrm{Mortality\; rate,\; under-5\; (per\; 1,000\; live\; births)\; -\; Algeria}\\ \mathrm{Quandl\; WWDI/DZA\_SH\_DYN\_MORT}\\ \mathrm{up\; to\; 65\; rows\; (annual),\; 1\; column}\\ \mathrm{1954-12-31\; -\; 2018-12-31}\end{array}\right]\end{array}\right]$

The DataSets[Reference] command was introduced in Maple 2015.

For more information on Maple 2015 changes, see Updates in Maple 2015.