A data processing apparatus that processes data including a plurality of spectra includes a group setting unit, an extracted data generation unit, and a base vector obtaining unit. The group setting unit classifies the plurality of spectra into a plurality of groups. The extracted data generation unit selects at least one spectrum from each of the groups set by the group setting unit and generates extracted data including the selected spectra. The base vector obtaining unit obtains, from the extracted data generated by the extracted data generation unit, base vectors for attributing the spectra to corresponding components.