Filtering Methods

Catalog.iloc	Returns the position-indexer for the catalog
Catalog.loc	Returns the label-indexer for the catalog
Catalog.query(expr)	Filters catalog and respective margin, if it exists, using a complex query expression
Catalog.rename(columns)	Renames catalog columns (not indices) and that of its margin if it exists using a dictionary or function mapping.
Catalog.head([n])	Returns a few rows of initial data for previewing purposes.
Catalog.tail([n])	Returns a few rows of data from the end of the catalog for previewing purposes.
Catalog.sample(partition_id[, n, seed])	Returns a few randomly sampled rows from a given partition.
Catalog.random_sample([n, seed])	Returns a few randomly sampled rows, like self.sample(), except that it randomly samples all partitions in order to fulfill the rows.
Catalog.__getitem__(item)	Select a column or columns from the catalog.