parquet_column_types {nanoparquet}

Map between R and Parquet data types

Description

This function works two ways. It can map the R types of a data frame to Parquet types, to see how write_parquet() would write out the data frame. It can also map the types of a Parquet file to R types, to see how read_parquet() would read the file into R.

Usage

parquet_column_types(x, options = parquet_options())

Arguments

x

Path to a Parquet file, or a data frame.

options

Nanoparquet options, see parquet_options().

Value

Data frame with columns:

• file_name: file name.

• name: column name.

• type: (low level) Parquet data type.

• r_type: the R type that corresponds to the Parquet type. Might be NA if read_parquet() cannot read this column. See nanoparquet-types for the type mapping rules.

• repetition_type: whether the column in REQUIRED (cannot be NA) or OPTIONAL (may be NA). REPEATED columns are not currently supported by nanoparquet.

• logical_type: Parquet logical type in a list column. An element has at least an entry called type, and potentially additional entries, e.g. bit_width, is_signed, etc.

See Also

parquet_metadata() to read more metadata, parquet_info() for a very short summary. parquet_schema() for the complete Parquet schema. read_parquet(), write_parquet(), nanoparquet-types.