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|
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# 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
# the License. You may obtain a copy of the License at
#
# 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.
#
import sys
import warnings
import json
if sys.version >= '3':
basestring = unicode = str
else:
from itertools import imap as map
from py4j.protocol import Py4JError
from pyspark.rdd import RDD, _prepare_for_python_RDD, ignore_unicode_prefix
from pyspark.serializers import AutoBatchedSerializer, PickleSerializer
from pyspark.sql import since
from pyspark.sql.types import Row, StringType, StructType, _verify_type, \
_infer_schema, _has_nulltype, _merge_type, _create_converter
from pyspark.sql.dataframe import DataFrame
from pyspark.sql.readwriter import DataFrameReader
from pyspark.sql.utils import install_exception_handler
from pyspark.sql.functions import UserDefinedFunction
try:
import pandas
has_pandas = True
except Exception:
has_pandas = False
__all__ = ["SQLContext", "HiveContext", "UDFRegistration"]
def _monkey_patch_RDD(sqlContext):
def toDF(self, schema=None, sampleRatio=None):
"""
Converts current :class:`RDD` into a :class:`DataFrame`
This is a shorthand for ``sqlContext.createDataFrame(rdd, schema, sampleRatio)``
:param schema: a StructType or list of names of columns
:param samplingRatio: the sample ratio of rows used for inferring
:return: a DataFrame
>>> rdd.toDF().collect()
[Row(name=u'Alice', age=1)]
"""
return sqlContext.createDataFrame(self, schema, sampleRatio)
RDD.toDF = toDF
class SQLContext(object):
"""Main entry point for Spark SQL functionality.
A SQLContext can be used create :class:`DataFrame`, register :class:`DataFrame` as
tables, execute SQL over tables, cache tables, and read parquet files.
:param sparkContext: The :class:`SparkContext` backing this SQLContext.
:param sqlContext: An optional JVM Scala SQLContext. If set, we do not instantiate a new
SQLContext in the JVM, instead we make all calls to this object.
"""
@ignore_unicode_prefix
def __init__(self, sparkContext, sqlContext=None):
"""Creates a new SQLContext.
>>> from datetime import datetime
>>> sqlContext = SQLContext(sc)
>>> allTypes = sc.parallelize([Row(i=1, s="string", d=1.0, l=1,
... b=True, list=[1, 2, 3], dict={"s": 0}, row=Row(a=1),
... time=datetime(2014, 8, 1, 14, 1, 5))])
>>> df = allTypes.toDF()
>>> df.registerTempTable("allTypes")
>>> sqlContext.sql('select i+1, d+1, not b, list[1], dict["s"], time, row.a '
... 'from allTypes where b and i > 0').collect()
[Row(_c0=2, _c1=2.0, _c2=False, _c3=2, _c4=0, \
time=datetime.datetime(2014, 8, 1, 14, 1, 5), a=1)]
>>> df.map(lambda x: (x.i, x.s, x.d, x.l, x.b, x.time, x.row.a, x.list)).collect()
[(1, u'string', 1.0, 1, True, datetime.datetime(2014, 8, 1, 14, 1, 5), 1, [1, 2, 3])]
"""
self._sc = sparkContext
self._jsc = self._sc._jsc
self._jvm = self._sc._jvm
self._scala_SQLContext = sqlContext
_monkey_patch_RDD(self)
install_exception_handler()
@property
def _ssql_ctx(self):
"""Accessor for the JVM Spark SQL context.
Subclasses can override this property to provide their own
JVM Contexts.
"""
if self._scala_SQLContext is None:
self._scala_SQLContext = self._jvm.SQLContext(self._jsc.sc())
return self._scala_SQLContext
@since(1.3)
def setConf(self, key, value):
"""Sets the given Spark SQL configuration property.
"""
self._ssql_ctx.setConf(key, value)
@since(1.3)
def getConf(self, key, defaultValue):
"""Returns the value of Spark SQL configuration property for the given key.
If the key is not set, returns defaultValue.
"""
return self._ssql_ctx.getConf(key, defaultValue)
@property
@since("1.3.1")
def udf(self):
"""Returns a :class:`UDFRegistration` for UDF registration.
:return: :class:`UDFRegistration`
"""
return UDFRegistration(self)
@since(1.4)
def range(self, start, end=None, step=1, numPartitions=None):
"""
Create a :class:`DataFrame` with single LongType column named `id`,
containing elements in a range from `start` to `end` (exclusive) with
step value `step`.
:param start: the start value
:param end: the end value (exclusive)
:param step: the incremental step (default: 1)
:param numPartitions: the number of partitions of the DataFrame
:return: :class:`DataFrame`
>>> sqlContext.range(1, 7, 2).collect()
[Row(id=1), Row(id=3), Row(id=5)]
If only one argument is specified, it will be used as the end value.
>>> sqlContext.range(3).collect()
[Row(id=0), Row(id=1), Row(id=2)]
"""
if numPartitions is None:
numPartitions = self._sc.defaultParallelism
if end is None:
jdf = self._ssql_ctx.range(0, int(start), int(step), int(numPartitions))
else:
jdf = self._ssql_ctx.range(int(start), int(end), int(step), int(numPartitions))
return DataFrame(jdf, self)
@ignore_unicode_prefix
@since(1.2)
def registerFunction(self, name, f, returnType=StringType()):
"""Registers a lambda function as a UDF so it can be used in SQL statements.
In addition to a name and the function itself, the return type can be optionally specified.
When the return type is not given it default to a string and conversion will automatically
be done. For any other return type, the produced object must match the specified type.
:param name: name of the UDF
:param samplingRatio: lambda function
:param returnType: a :class:`DataType` object
>>> sqlContext.registerFunction("stringLengthString", lambda x: len(x))
>>> sqlContext.sql("SELECT stringLengthString('test')").collect()
[Row(_c0=u'4')]
>>> from pyspark.sql.types import IntegerType
>>> sqlContext.registerFunction("stringLengthInt", lambda x: len(x), IntegerType())
>>> sqlContext.sql("SELECT stringLengthInt('test')").collect()
[Row(_c0=4)]
>>> from pyspark.sql.types import IntegerType
>>> sqlContext.udf.register("stringLengthInt", lambda x: len(x), IntegerType())
>>> sqlContext.sql("SELECT stringLengthInt('test')").collect()
[Row(_c0=4)]
"""
udf = UserDefinedFunction(f, returnType, name)
self._ssql_ctx.udf().registerPython(name, udf._judf)
def _inferSchemaFromList(self, data):
"""
Infer schema from list of Row or tuple.
:param data: list of Row or tuple
:return: StructType
"""
if not data:
raise ValueError("can not infer schema from empty dataset")
first = data[0]
if type(first) is dict:
warnings.warn("inferring schema from dict is deprecated,"
"please use pyspark.sql.Row instead")
schema = _infer_schema(first)
if _has_nulltype(schema):
for r in data:
schema = _merge_type(schema, _infer_schema(r))
if not _has_nulltype(schema):
break
else:
raise ValueError("Some of types cannot be determined after inferring")
return schema
def _inferSchema(self, rdd, samplingRatio=None):
"""
Infer schema from an RDD of Row or tuple.
:param rdd: an RDD of Row or tuple
:param samplingRatio: sampling ratio, or no sampling (default)
:return: StructType
"""
first = rdd.first()
if not first:
raise ValueError("The first row in RDD is empty, "
"can not infer schema")
if type(first) is dict:
warnings.warn("Using RDD of dict to inferSchema is deprecated. "
"Use pyspark.sql.Row instead")
if samplingRatio is None:
schema = _infer_schema(first)
if _has_nulltype(schema):
for row in rdd.take(100)[1:]:
schema = _merge_type(schema, _infer_schema(row))
if not _has_nulltype(schema):
break
else:
raise ValueError("Some of types cannot be determined by the "
"first 100 rows, please try again with sampling")
else:
if samplingRatio < 0.99:
rdd = rdd.sample(False, float(samplingRatio))
schema = rdd.map(_infer_schema).reduce(_merge_type)
return schema
@ignore_unicode_prefix
def inferSchema(self, rdd, samplingRatio=None):
"""
.. note:: Deprecated in 1.3, use :func:`createDataFrame` instead.
"""
warnings.warn("inferSchema is deprecated, please use createDataFrame instead.")
if isinstance(rdd, DataFrame):
raise TypeError("Cannot apply schema to DataFrame")
return self.createDataFrame(rdd, None, samplingRatio)
@ignore_unicode_prefix
def applySchema(self, rdd, schema):
"""
.. note:: Deprecated in 1.3, use :func:`createDataFrame` instead.
"""
warnings.warn("applySchema is deprecated, please use createDataFrame instead")
if isinstance(rdd, DataFrame):
raise TypeError("Cannot apply schema to DataFrame")
if not isinstance(schema, StructType):
raise TypeError("schema should be StructType, but got %s" % type(schema))
return self.createDataFrame(rdd, schema)
def _createFromRDD(self, rdd, schema, samplingRatio):
"""
Create an RDD for DataFrame from an existing RDD, returns the RDD and schema.
"""
if schema is None or isinstance(schema, (list, tuple)):
struct = self._inferSchema(rdd, samplingRatio)
converter = _create_converter(struct)
rdd = rdd.map(converter)
if isinstance(schema, (list, tuple)):
for i, name in enumerate(schema):
struct.fields[i].name = name
struct.names[i] = name
schema = struct
elif isinstance(schema, StructType):
# take the first few rows to verify schema
rows = rdd.take(10)
for row in rows:
_verify_type(row, schema)
else:
raise TypeError("schema should be StructType or list or None, but got: %s" % schema)
# convert python objects to sql data
rdd = rdd.map(schema.toInternal)
return rdd, schema
def _createFromLocal(self, data, schema):
"""
Create an RDD for DataFrame from an list or pandas.DataFrame, returns
the RDD and schema.
"""
if has_pandas and isinstance(data, pandas.DataFrame):
if schema is None:
schema = [str(x) for x in data.columns]
data = [r.tolist() for r in data.to_records(index=False)]
# make sure data could consumed multiple times
if not isinstance(data, list):
data = list(data)
if schema is None or isinstance(schema, (list, tuple)):
struct = self._inferSchemaFromList(data)
if isinstance(schema, (list, tuple)):
for i, name in enumerate(schema):
struct.fields[i].name = name
struct.names[i] = name
schema = struct
elif isinstance(schema, StructType):
for row in data:
_verify_type(row, schema)
else:
raise TypeError("schema should be StructType or list or None, but got: %s" % schema)
# convert python objects to sql data
data = [schema.toInternal(row) for row in data]
return self._sc.parallelize(data), schema
@since(1.3)
@ignore_unicode_prefix
def createDataFrame(self, data, schema=None, samplingRatio=None):
"""
Creates a :class:`DataFrame` from an :class:`RDD` of :class:`tuple`/:class:`list`,
list or :class:`pandas.DataFrame`.
When ``schema`` is a list of column names, the type of each column
will be inferred from ``data``.
When ``schema`` is ``None``, it will try to infer the schema (column names and types)
from ``data``, which should be an RDD of :class:`Row`,
or :class:`namedtuple`, or :class:`dict`.
If schema inference is needed, ``samplingRatio`` is used to determined the ratio of
rows used for schema inference. The first row will be used if ``samplingRatio`` is ``None``.
:param data: an RDD of :class:`Row`/:class:`tuple`/:class:`list`/:class:`dict`,
:class:`list`, or :class:`pandas.DataFrame`.
:param schema: a :class:`StructType` or list of column names. default None.
:param samplingRatio: the sample ratio of rows used for inferring
:return: :class:`DataFrame`
>>> l = [('Alice', 1)]
>>> sqlContext.createDataFrame(l).collect()
[Row(_1=u'Alice', _2=1)]
>>> sqlContext.createDataFrame(l, ['name', 'age']).collect()
[Row(name=u'Alice', age=1)]
>>> d = [{'name': 'Alice', 'age': 1}]
>>> sqlContext.createDataFrame(d).collect()
[Row(age=1, name=u'Alice')]
>>> rdd = sc.parallelize(l)
>>> sqlContext.createDataFrame(rdd).collect()
[Row(_1=u'Alice', _2=1)]
>>> df = sqlContext.createDataFrame(rdd, ['name', 'age'])
>>> df.collect()
[Row(name=u'Alice', age=1)]
>>> from pyspark.sql import Row
>>> Person = Row('name', 'age')
>>> person = rdd.map(lambda r: Person(*r))
>>> df2 = sqlContext.createDataFrame(person)
>>> df2.collect()
[Row(name=u'Alice', age=1)]
>>> from pyspark.sql.types import *
>>> schema = StructType([
... StructField("name", StringType(), True),
... StructField("age", IntegerType(), True)])
>>> df3 = sqlContext.createDataFrame(rdd, schema)
>>> df3.collect()
[Row(name=u'Alice', age=1)]
>>> sqlContext.createDataFrame(df.toPandas()).collect() # doctest: +SKIP
[Row(name=u'Alice', age=1)]
>>> sqlContext.createDataFrame(pandas.DataFrame([[1, 2]]).collect()) # doctest: +SKIP
[Row(0=1, 1=2)]
"""
if isinstance(data, DataFrame):
raise TypeError("data is already a DataFrame")
if isinstance(data, RDD):
rdd, schema = self._createFromRDD(data, schema, samplingRatio)
else:
rdd, schema = self._createFromLocal(data, schema)
jrdd = self._jvm.SerDeUtil.toJavaArray(rdd._to_java_object_rdd())
jdf = self._ssql_ctx.applySchemaToPythonRDD(jrdd.rdd(), schema.json())
df = DataFrame(jdf, self)
df._schema = schema
return df
@since(1.3)
def registerDataFrameAsTable(self, df, tableName):
"""Registers the given :class:`DataFrame` as a temporary table in the catalog.
Temporary tables exist only during the lifetime of this instance of :class:`SQLContext`.
>>> sqlContext.registerDataFrameAsTable(df, "table1")
"""
if (df.__class__ is DataFrame):
self._ssql_ctx.registerDataFrameAsTable(df._jdf, tableName)
else:
raise ValueError("Can only register DataFrame as table")
def parquetFile(self, *paths):
"""Loads a Parquet file, returning the result as a :class:`DataFrame`.
.. note:: Deprecated in 1.4, use :func:`DataFrameReader.parquet` instead.
>>> sqlContext.parquetFile('python/test_support/sql/parquet_partitioned').dtypes
[('name', 'string'), ('year', 'int'), ('month', 'int'), ('day', 'int')]
"""
warnings.warn("parquetFile is deprecated. Use read.parquet() instead.")
gateway = self._sc._gateway
jpaths = gateway.new_array(gateway.jvm.java.lang.String, len(paths))
for i in range(0, len(paths)):
jpaths[i] = paths[i]
jdf = self._ssql_ctx.parquetFile(jpaths)
return DataFrame(jdf, self)
def jsonFile(self, path, schema=None, samplingRatio=1.0):
"""Loads a text file storing one JSON object per line as a :class:`DataFrame`.
.. note:: Deprecated in 1.4, use :func:`DataFrameReader.json` instead.
>>> sqlContext.jsonFile('python/test_support/sql/people.json').dtypes
[('age', 'bigint'), ('name', 'string')]
"""
warnings.warn("jsonFile is deprecated. Use read.json() instead.")
if schema is None:
df = self._ssql_ctx.jsonFile(path, samplingRatio)
else:
scala_datatype = self._ssql_ctx.parseDataType(schema.json())
df = self._ssql_ctx.jsonFile(path, scala_datatype)
return DataFrame(df, self)
@ignore_unicode_prefix
@since(1.0)
def jsonRDD(self, rdd, schema=None, samplingRatio=1.0):
"""Loads an RDD storing one JSON object per string as a :class:`DataFrame`.
If the schema is provided, applies the given schema to this JSON dataset.
Otherwise, it samples the dataset with ratio ``samplingRatio`` to determine the schema.
>>> df1 = sqlContext.jsonRDD(json)
>>> df1.first()
Row(field1=1, field2=u'row1', field3=Row(field4=11, field5=None), field6=None)
>>> df2 = sqlContext.jsonRDD(json, df1.schema)
>>> df2.first()
Row(field1=1, field2=u'row1', field3=Row(field4=11, field5=None), field6=None)
>>> from pyspark.sql.types import *
>>> schema = StructType([
... StructField("field2", StringType()),
... StructField("field3",
... StructType([StructField("field5", ArrayType(IntegerType()))]))
... ])
>>> df3 = sqlContext.jsonRDD(json, schema)
>>> df3.first()
Row(field2=u'row1', field3=Row(field5=None))
"""
def func(iterator):
for x in iterator:
if not isinstance(x, basestring):
x = unicode(x)
if isinstance(x, unicode):
x = x.encode("utf-8")
yield x
keyed = rdd.mapPartitions(func)
keyed._bypass_serializer = True
jrdd = keyed._jrdd.map(self._jvm.BytesToString())
if schema is None:
df = self._ssql_ctx.jsonRDD(jrdd.rdd(), samplingRatio)
else:
scala_datatype = self._ssql_ctx.parseDataType(schema.json())
df = self._ssql_ctx.jsonRDD(jrdd.rdd(), scala_datatype)
return DataFrame(df, self)
def load(self, path=None, source=None, schema=None, **options):
"""Returns the dataset in a data source as a :class:`DataFrame`.
.. note:: Deprecated in 1.4, use :func:`DataFrameReader.load` instead.
"""
warnings.warn("load is deprecated. Use read.load() instead.")
return self.read.load(path, source, schema, **options)
@since(1.3)
def createExternalTable(self, tableName, path=None, source=None, schema=None, **options):
"""Creates an external table based on the dataset in a data source.
It returns the DataFrame associated with the external table.
The data source is specified by the ``source`` and a set of ``options``.
If ``source`` is not specified, the default data source configured by
``spark.sql.sources.default`` will be used.
Optionally, a schema can be provided as the schema of the returned :class:`DataFrame` and
created external table.
:return: :class:`DataFrame`
"""
if path is not None:
options["path"] = path
if source is None:
source = self.getConf("spark.sql.sources.default",
"org.apache.spark.sql.parquet")
if schema is None:
df = self._ssql_ctx.createExternalTable(tableName, source, options)
else:
if not isinstance(schema, StructType):
raise TypeError("schema should be StructType")
scala_datatype = self._ssql_ctx.parseDataType(schema.json())
df = self._ssql_ctx.createExternalTable(tableName, source, scala_datatype,
options)
return DataFrame(df, self)
@ignore_unicode_prefix
@since(1.0)
def sql(self, sqlQuery):
"""Returns a :class:`DataFrame` representing the result of the given query.
:return: :class:`DataFrame`
>>> sqlContext.registerDataFrameAsTable(df, "table1")
>>> df2 = sqlContext.sql("SELECT field1 AS f1, field2 as f2 from table1")
>>> df2.collect()
[Row(f1=1, f2=u'row1'), Row(f1=2, f2=u'row2'), Row(f1=3, f2=u'row3')]
"""
return DataFrame(self._ssql_ctx.sql(sqlQuery), self)
@since(1.0)
def table(self, tableName):
"""Returns the specified table as a :class:`DataFrame`.
:return: :class:`DataFrame`
>>> sqlContext.registerDataFrameAsTable(df, "table1")
>>> df2 = sqlContext.table("table1")
>>> sorted(df.collect()) == sorted(df2.collect())
True
"""
return DataFrame(self._ssql_ctx.table(tableName), self)
@ignore_unicode_prefix
@since(1.3)
def tables(self, dbName=None):
"""Returns a :class:`DataFrame` containing names of tables in the given database.
If ``dbName`` is not specified, the current database will be used.
The returned DataFrame has two columns: ``tableName`` and ``isTemporary``
(a column with :class:`BooleanType` indicating if a table is a temporary one or not).
:param dbName: string, name of the database to use.
:return: :class:`DataFrame`
>>> sqlContext.registerDataFrameAsTable(df, "table1")
>>> df2 = sqlContext.tables()
>>> df2.filter("tableName = 'table1'").first()
Row(tableName=u'table1', isTemporary=True)
"""
if dbName is None:
return DataFrame(self._ssql_ctx.tables(), self)
else:
return DataFrame(self._ssql_ctx.tables(dbName), self)
@since(1.3)
def tableNames(self, dbName=None):
"""Returns a list of names of tables in the database ``dbName``.
:param dbName: string, name of the database to use. Default to the current database.
:return: list of table names, in string
>>> sqlContext.registerDataFrameAsTable(df, "table1")
>>> "table1" in sqlContext.tableNames()
True
>>> "table1" in sqlContext.tableNames("db")
True
"""
if dbName is None:
return [name for name in self._ssql_ctx.tableNames()]
else:
return [name for name in self._ssql_ctx.tableNames(dbName)]
@since(1.0)
def cacheTable(self, tableName):
"""Caches the specified table in-memory."""
self._ssql_ctx.cacheTable(tableName)
@since(1.0)
def uncacheTable(self, tableName):
"""Removes the specified table from the in-memory cache."""
self._ssql_ctx.uncacheTable(tableName)
@since(1.3)
def clearCache(self):
"""Removes all cached tables from the in-memory cache. """
self._ssql_ctx.clearCache()
@property
@since(1.4)
def read(self):
"""
Returns a :class:`DataFrameReader` that can be used to read data
in as a :class:`DataFrame`.
:return: :class:`DataFrameReader`
"""
return DataFrameReader(self)
class HiveContext(SQLContext):
"""A variant of Spark SQL that integrates with data stored in Hive.
Configuration for Hive is read from ``hive-site.xml`` on the classpath.
It supports running both SQL and HiveQL commands.
:param sparkContext: The SparkContext to wrap.
:param hiveContext: An optional JVM Scala HiveContext. If set, we do not instantiate a new
:class:`HiveContext` in the JVM, instead we make all calls to this object.
"""
def __init__(self, sparkContext, hiveContext=None):
SQLContext.__init__(self, sparkContext)
if hiveContext:
self._scala_HiveContext = hiveContext
@property
def _ssql_ctx(self):
try:
if not hasattr(self, '_scala_HiveContext'):
self._scala_HiveContext = self._get_hive_ctx()
return self._scala_HiveContext
except Py4JError as e:
raise Exception("You must build Spark with Hive. "
"Export 'SPARK_HIVE=true' and run "
"build/sbt assembly", e)
def _get_hive_ctx(self):
return self._jvm.HiveContext(self._jsc.sc())
def refreshTable(self, tableName):
"""Invalidate and refresh all the cached the metadata of the given
table. For performance reasons, Spark SQL or the external data source
library it uses might cache certain metadata about a table, such as the
location of blocks. When those change outside of Spark SQL, users should
call this function to invalidate the cache.
"""
self._ssql_ctx.refreshTable(tableName)
class UDFRegistration(object):
"""Wrapper for user-defined function registration."""
def __init__(self, sqlContext):
self.sqlContext = sqlContext
def register(self, name, f, returnType=StringType()):
return self.sqlContext.registerFunction(name, f, returnType)
register.__doc__ = SQLContext.registerFunction.__doc__
def _test():
import os
import doctest
from pyspark.context import SparkContext
from pyspark.sql import Row, SQLContext
import pyspark.sql.context
os.chdir(os.environ["SPARK_HOME"])
globs = pyspark.sql.context.__dict__.copy()
sc = SparkContext('local[4]', 'PythonTest')
globs['sc'] = sc
globs['sqlContext'] = SQLContext(sc)
globs['rdd'] = rdd = sc.parallelize(
[Row(field1=1, field2="row1"),
Row(field1=2, field2="row2"),
Row(field1=3, field2="row3")]
)
globs['df'] = rdd.toDF()
jsonStrings = [
'{"field1": 1, "field2": "row1", "field3":{"field4":11}}',
'{"field1" : 2, "field3":{"field4":22, "field5": [10, 11]},'
'"field6":[{"field7": "row2"}]}',
'{"field1" : null, "field2": "row3", '
'"field3":{"field4":33, "field5": []}}'
]
globs['jsonStrings'] = jsonStrings
globs['json'] = sc.parallelize(jsonStrings)
(failure_count, test_count) = doctest.testmod(
pyspark.sql.context, globs=globs,
optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE)
globs['sc'].stop()
if failure_count:
exit(-1)
if __name__ == "__main__":
_test()
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