Apparatuses and methods for extracting ordered data sub-components from a data item are disclosed. A received data item has a data structure to accommodate multiple data sub-components. The data item indicates which data sub-components are valid. Adders sum respective subsets of indications of the valid data sub-component positions, with each adder covering one more position than the previous adder. Transitions of the counts generated by the respective adders are used to determine the ordinal valid data sub-component positions in the data item, which can then be output on the basis of the data item and the identified transition positions. Without requiring feedback paths from an identified earlier ordinal position to identify a later ordinal position, the set of ordered data sub-components can be extracted more quickly.