Added
- `Peptide.counts` method to get the number of occurences of each amino acid in the peptide.
- `Peptide.frequencies` to get the frequencies of each amino acid in the peptide.
- `Peptide.pcp_descriptors` to compute the PCP descriptors from Mathura & Braun (2001).
- `Peptide.sneath_vectors` to compute the descriptors from Sneath (1966).
- Hydrophilicity descriptors from Barley (2018).
- `Peptide.structural_class` to predict the structural class of a protein using one of three reference datasets and one of four distance metrics.
Changed
- `Peptide.aliphatic_index` now supports unknown Leu/Ile residue (code *J*).
- Swap order of `Peptide.hydrophobic_moment` arguments for consistency with profile methods.
- Some `Peptide` functions now support vectorized code using `numpy` if available.