AgenticSpark opened a new pull request, #56726:
URL: https://github.com/apache/spark/pull/56726
### What changes were proposed in this pull request?
This adds a `_name` property to the PySpark `Column` class that returns the
column's name, alias, or expression as a string -- the same string shown
inside
`Column.__repr__` (`Column<'...'>`). It is implemented for both Spark Classic
(`self._jc.toString()`) and Spark Connect (`self._expr.__repr__()`).
```python
>>> from pyspark.sql import functions as sf
>>> df = spark.createDataFrame([(2, "Alice")], ["age", "name"])
>>> df.age._name
'age'
>>> sf.col("value")._name
'value'
>>> sf.col("a").cast("int")._name
'CAST(a AS INT)'
```
The leading underscore intentionally avoids a collision with the existing
`Column.name` method, which is an alias for `Column.alias`.
### Why are the changes needed?
Requested in
[SPARK-38483](https://issues.apache.org/jira/browse/SPARK-38483).
Having the name available as an attribute enables convenient patterns, e.g.
re-aliasing an expression with the source column's name, or branching on a
column's name inside a helper function:
```python
values = sf.col("values")
distinct_values = sf.array_distinct(values).alias(values._name)
def custom_function(col):
return col.cast("int") if col._name == "my_column" else
col.cast("string")
```
Previously the name was only obtainable by parsing `repr(col)`.
### Does this PR introduce _any_ user-facing change?
Yes -- a new `Column._name` property is available. There is no change to any
existing behavior.
### How was this patch tested?
Added `test_name_property` to `ColumnTestsMixin`, so it runs under both the
classic (`pyspark.sql.tests.test_column`) and Spark Connect parity
(`pyspark.sql.tests.connect.test_parity_column`) suites. It checks concrete
values and the invariant `repr(col) == "Column<'%s'>" % col._name`. Doctests
were also added on the new property.
### Was this patch authored or co-authored using generative AI tooling?
Generated-by: GitHub Copilot CLI (Claude Opus 4.8)
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