kumoai.experimental.rfm.LocalTable

class kumoai.experimental.rfm.LocalTable

Bases: object

A table backed by a pandas.DataFrame.

A LocalTable fully specifies the relevant metadata, i.e. selected columns, column semantic types, primary keys and time columns. LocalTable is used to create a LocalGraph.

import pandas as pd
import kumoai.experimental.rfm as rfm

# Load data from a CSV file:
df = pd.read_csv("data.csv")

# Create a table from a `pandas.DataFrame` and infer its metadata ...
table = rfm.LocalTable(df, name="my_table").infer_metadata()

# ... or create a table explicitly:
table = rfm.LocalTable(
    df=df,
    name="my_table",
    primary_key="id",
    time_column="time",
    end_time_column=None,
)

# Verify metadata:
table.print_metadata()

# Change the semantic type of a column:
table[column].stype = "text"

Parameters:

• df (DataFrame) – The data frame to create the table from.

• name (str) – The name of the table.

• primary_key (Optional[str]) – The name of the primary key of this table, if it exists.

• time_column (Optional[str]) – The name of the time column of this table, if it exists.

• end_time_column (Optional[str]) – The name of the end time column of this table, if it exists.

__init__(df, name, primary_key=None, time_column=None, end_time_column=None)

property name: str

The name of the table.

has_column(name)

Returns True if this table holds a column with name name; False otherwise.

Return type:

bool

column(name)

Returns the data column named with name name in this table.

Parameters:

name (str) – The name of the column.

Raises:

KeyError – If name is not present in this table.

Return type:

Column

property columns: List[Column]

Returns a list of Column objects that represent the columns in this table.

add_column(name)

Adds a column to this table.

Parameters:

name (str) – The name of the column.

Raises:

KeyError – If name is already present in this table.

Return type:

Column

remove_column(name)

Removes a column from this table.

Parameters:

name (str) – The name of the column.

Raises:

KeyError – If name is not present in this table.

Return type:

Self

has_primary_key()

Returns True` if this table has a primary key; False otherwise.

Return type:

bool

property primary_key: Column | None

The primary key column of this table.

The getter returns the primary key column of this table, or None if no such primary key is present.

The setter sets a column as a primary key on this table, and raises a ValueError if the primary key has a non-ID semantic type or if the column name does not match a column in the data frame.

has_time_column()

Returns True if this table has a time column; False otherwise.

Return type:

bool

property time_column: Column | None

The time column of this table.

The getter returns the time column of this table, or None if no such time column is present.

The setter sets a column as a time column on this table, and raises a ValueError if the time column has a non-timestamp semantic type or if the column name does not match a column in the data frame.

has_end_time_column()

Returns True if this table has an end time column; False otherwise.

Return type:

bool

property end_time_column: Column | None

The end time column of this table.

The getter returns the end time column of this table, or None if no such end time column is present.

The setter sets a column as an end time column on this table, and raises a ValueError if the end time column has a non-timestamp semantic type or if the column name does not match a column in the data frame.

property metadata: DataFrame

Returns a pandas.DataFrame object containing metadata information about the columns in this table.

The returned dataframe has columns name, dtype, stype, is_primary_key, is_time_column and is_end_time_column, which provide an aggregate view of the properties of the columns of this table.

Example

>>> 
>>> import kumoai.experimental.rfm as rfm
>>> table = rfm.LocalTable(df=..., name=...).infer_metadata()
>>> table.metadata
    name        dtype    stype  is_primary_key  is_time_column  is_end_time_column
0   CustomerID  float64  ID     True            False           False

print_metadata()

Prints the metadata() of the table.

Return type:

None

infer_metadata(verbose=True)

Infers metadata, i.e., primary keys and time columns, in the table.

Parameters:

verbose (bool) – Whether to print verbose output.

Return type:

Self