spark-instrumented-optimizer/python/pyspark/_globals.py
hyukjinkwon 4b4ee26010 [SPARK-23328][PYTHON] Disallow default value None in na.replace/replace when 'to_replace' is not a dictionary
## What changes were proposed in this pull request?

This PR proposes to disallow default value None when 'to_replace' is not a dictionary.

It seems weird we set the default value of `value` to `None` and we ended up allowing the case as below:

```python
>>> df.show()
```
```
+----+------+-----+
| age|height| name|
+----+------+-----+
|  10|    80|Alice|
...
```

```python
>>> df.na.replace('Alice').show()
```
```
+----+------+----+
| age|height|name|
+----+------+----+
|  10|    80|null|
...
```

**After**

This PR targets to disallow the case above:

```python
>>> df.na.replace('Alice').show()
```
```
...
TypeError: value is required when to_replace is not a dictionary.
```

while we still allow when `to_replace` is a dictionary:

```python
>>> df.na.replace({'Alice': None}).show()
```
```
+----+------+----+
| age|height|name|
+----+------+----+
|  10|    80|null|
...
```

## How was this patch tested?

Manually tested, tests were added in `python/pyspark/sql/tests.py` and doctests were fixed.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #20499 from HyukjinKwon/SPARK-19454-followup.
2018-02-09 14:21:10 +08:00

71 lines
2.2 KiB
Python

#
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# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
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# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""
Module defining global singleton classes.
This module raises a RuntimeError if an attempt to reload it is made. In that
way the identities of the classes defined here are fixed and will remain so
even if pyspark itself is reloaded. In particular, a function like the following
will still work correctly after pyspark is reloaded:
def foo(arg=pyspark._NoValue):
if arg is pyspark._NoValue:
...
See gh-7844 for a discussion of the reload problem that motivated this module.
Note that this approach is taken after from NumPy.
"""
__ALL__ = ['_NoValue']
# Disallow reloading this module so as to preserve the identities of the
# classes defined here.
if '_is_loaded' in globals():
raise RuntimeError('Reloading pyspark._globals is not allowed')
_is_loaded = True
class _NoValueType(object):
"""Special keyword value.
The instance of this class may be used as the default value assigned to a
deprecated keyword in order to check if it has been given a user defined
value.
This class was copied from NumPy.
"""
__instance = None
def __new__(cls):
# ensure that only one instance exists
if not cls.__instance:
cls.__instance = super(_NoValueType, cls).__new__(cls)
return cls.__instance
# needed for python 2 to preserve identity through a pickle
def __reduce__(self):
return (self.__class__, ())
def __repr__(self):
return "<no value>"
_NoValue = _NoValueType()