Query Iterators#
Query functions typically return objects that behave like iterators.
These objects do not allow for direct access to individual items (like iter[0]), but do allow for looping through
them.
The reason for returning an iterator rather than a list is that an iterator will handle batching to the server. Since a query can return many items, they must be retrieved in batches. The iterator does this automatically, but does so incrementally as iteration continues.
>>> query_it = client.query_molecules(molecular_formula='N2')
>>> for mol in query_it:
... print(mol.id, mol.identifiers.molecular_formula)
371 N2
372 N2
If you need all items as a list, then you can use the list constructor, which will use the iterator to fill in the
list. In this case, all the records will be fetched from the server as the list is being created.
>>> query_it = client.query_molecules(molecular_formula='N2')
>>> mols = list(query_it)
>>> print(len(mols))
621