Pandas Series: factorize() function

Last update on April 21 2020 10:47:34 (UTC/GMT +8 hours)

Encode the object in Pandas

The factorize() function is used to encode the object as an enumerated type or categorical variable.

This method is useful for obtaining a numeric representation of an array when all that matters is identifying distinct values. factorize is available as both a top-level function pandas.factorize(), and as a method Series.factorize() and Index.factorize().

Syntax:

Series.factorize(self, sort=False, na_sentinel=-1)

Parameters:

Name	Description	Type/Default Value	Required / Optional
sort	Sort uniques and shuffle labels to maintain the relationship.	boolean Default Value: False	Required
na_sentinel	Value to mark “not found”.	int Default Value: 1	Required

Returns:

labels - ndarray
An integer ndarray that’s an indexer into uniques. uniques.take(labels) will have the same values as values.
uniques - ndarray, Index, or Categorical
The unique valid values. When values is Categorical, uniques is a Categorical. When values is some other pandas object, an Index is returned. Otherwise, a 1-D ndarray is returned.

Example:

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