Reshape a metamet object from wide to long format
reshape_wide_to_long.RdThis function converts the component data tables of a metamet (`mm`) object—`dt`, `dt_qc`, and `dt_ref`—from wide format to long format using `data.table::melt()`. It merges QC flags, reference values, and metadata into a single long-format `dt` table and removes the now-redundant `dt_qc` and `dt_ref` components.
Arguments
- mm
A metamet object (a list-like structure) containing at least the elements `dt`, `dt_qc`, `dt_ref`, and `dt_meta`. Each component must be a `data.table` with expected columns: * `dt`: `site`, `TIMESTAMP`, measurement columns * `dt_qc`: `site`, `TIMESTAMP`, `validator`, QC columns * `dt_ref`: `site`, `TIMESTAMP`, reference columns * `dt_meta`: includes `site`, `name_dt`, `type`, `name_icos`
Value
The modified metamet object, where: * `mm$dt` is now a long-format table containing measurement values, QC flags, validator names, reference values, and metadata. * `mm$dt_qc` and `mm$dt_ref` are set to `NULL` because their content has been merged into `mm$dt`.
Details
Internally, the function: 1. Melts each data table to long format. 2. Sets keys and performs keyed merges for efficient joining. 3. Annotates `mm$dt` with QC, reference, and metadata fields.
This function is designed for harmonising metamet objects before downstream validation and processing.