databricks.koalas.DataFrame.to_koalas¶
-
DataFrame.
to_koalas
(index_col: Union[str, List[str], None] = None) → databricks.koalas.frame.DataFrame[source]¶ Converts the existing DataFrame into a Koalas DataFrame.
This method is monkey-patched into Spark’s DataFrame and can be used to convert a Spark DataFrame into a Koalas DataFrame. If running on an existing Koalas DataFrame, the method returns itself.
If a Koalas DataFrame is converted to a Spark DataFrame and then back to Koalas, it will lose the index information and the original index will be turned into a normal column.
- Parameters
- index_col: str or list of str, optional, default: None
Index column of table in Spark.
See also
Examples
>>> df = ks.DataFrame({'col1': [1, 2], 'col2': [3, 4]}, columns=['col1', 'col2']) >>> df col1 col2 0 1 3 1 2 4
>>> spark_df = df.to_spark() >>> spark_df DataFrame[col1: bigint, col2: bigint]
>>> kdf = spark_df.to_koalas() >>> kdf col1 col2 0 1 3 1 2 4
We can specify the index columns.
>>> kdf = spark_df.to_koalas(index_col='col1') >>> kdf col2 col1 1 3 2 4
Calling to_koalas on a Koalas DataFrame simply returns itself.
>>> df.to_koalas() col1 col2 0 1 3 1 2 4