Transform

class lumen.transforms.base.Transform(*, controls, name)

Transform components implement transforms of DataFrame objects.

---

Parameters

controls

type: list
default: []
Parameters that should be exposed as widgets in the UI.

name

type: str
default: 'Transform'
String identifier for this object.

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Methods

Transform.apply(table: DataFrame) → DataFrame

Given a table transform it in some way and return it.

Parameters:

table (DataFrame) – The queried table as a DataFrame.

Returns:

A DataFrame containing the transformed data.

Return type:

DataFrame

Transform.to_spec(context: dict[str, Any] | None = None) → dict[str, Any]

Exports the full specification to reconstruct this component.

Return type:

Resolved and instantiated Component object

Types

Filter

Filter transform implement the filtering behavior of Filter components.

Filter.html

HistoryTransform type: history

HistoryTransform accumulates a history of the queried data.

HistoryTransform.html

Aggregate type: aggregate

Aggregate one or more columns or indexes, see pandas.DataFrame.groupby.

Aggregate.html

Sort type: sort

Sort on one or more columns, see pandas.DataFrame.sort_values.

Sort.html

Query type: query

Query applies the pandas.DataFrame.query method.

Query.html

Columns type: columns

Columns selects a subset of columns.

Columns.html

Astype type: as_type

Astype transforms the type of one or more columns.

Astype.html

Stack type: stack

Stack applies pandas.DataFrame.stack to the declared level.

Stack.html

Unstack type: unstack

Unstack applies pandas.DataFrame.unstack to the declared level.

Unstack.html

Iloc type: iloc

Iloc allows selecting the data with integer indexing, see pandas.DataFrame.iloc.

Iloc.html

Sample type: sample

Sample returns a random sample of items.

Sample.html

Compute type: compute

Compute turns a dask.dataframe.DataFrame into a pandas.DataFrame.

Compute.html

Pivot type: pivot

Pivot applies pandas.DataFrame.pivot given an index, columns, and values.

Pivot.html

PivotTable

PivotTable applies pandas.pivot_table` to the data.

PivotTable.html

Melt type: melt

Melt applies the pandas.melt operation given the id_vars and value_vars.

Melt.html

SetIndex type: set_index

SetIndex promotes DataFrame columns to indexes, see pandas.DataFrame.set_index.

SetIndex.html

ResetIndex type: reset_index

ResetIndex resets DataFrame indexes to columns or drops them, see pandas.DataFrame.reset_index

ResetIndex.html

Rename type: rename

Rename renames columns or indexes, see pandas.DataFrame.rename.

Rename.html

RenameAxis type: rename_axis

Set the name of the axis for the index or columns,

RenameAxis.html

Count type: count

Counts non-nan values in each column of the DataFrame and returns

Count.html

Sum type: sum

Sums numeric values in each column of the DataFrame and returns a

Sum.html

Eval type: eval

Applies an eval assignment expression to a DataFrame. The

Eval.html

DropNA type: dropna

DropNA drops rows with any missing values.

DropNA.html

Corr type: corr

Corr computes pairwise correlation of columns, excluding NA/null values.

Corr.html

project_lnglat type: project_lnglat

project_lnglat projects the given longitude/latitude columns to Web Mercator.

project_lnglat.html

SQLFormat type: sql_format

Format SQL expressions with parameterized replacements.

SQLFormat.html

SQLGroupBy type: sql_group_by

Performs a Group-By and aggregation

SQLGroupBy.html

SQLLimit type: sql_limit

Performs a LIMIT SQL operation on the query.

SQLLimit.html

SQLDistinct type: sql_distinct

SQLDistinct Transform

SQLDistinct.html

SQLCount type: sql_count

SQLCount Transform

SQLCount.html

SQLMinMax type: sql_minmax

SQLMinMax Transform

SQLMinMax.html

SQLColumns type: sql_columns

SQLColumns Transform

SQLColumns.html

SQLFilter type: sql_filter

SQLFilter Transform

SQLFilter.html

SQLOverride

SQLOverride Transform

SQLOverride.html

SQLSample type: sql_sample

Samples rows from a SQL query using TABLESAMPLE or similar functionality,

SQLSample.html

SQLRemoveSourceSeparator

Class to exclude the source and separator.

SQLRemoveSourceSeparator.html

SQLSelectFrom type: sql_select_from

SQLSelectFrom Transform

SQLSelectFrom.html