我在Python API中使用Spark 2.0.
我有一个数据框,其列为DateType()类型.我想在包含最新星期一的数据框中添加一列.
我可以这样做:
reg_schema = pyspark.sql.types.StructType([
pyspark.sql.types.StructField('AccountCreationDate', pyspark.sql.types.DateType(), True),
pyspark.sql.types.StructField('UserId', pyspark.sql.types.LongType(), True)
])
reg = spark.read.schema(reg_schema).option('header', True).csv(path_to_file)
reg = reg.withColumn('monday',
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate,'E') == 'Mon',
reg.AccountCreationDate).otherwise(
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate,'E') == 'Tue',
pyspark.sql.functions.date_sub(reg.AccountCreationDate, 1)).otherwise(
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate, 'E') == 'Wed',
pyspark.sql.functions.date_sub(reg.AccountCreationDate, 2)).otherwise(
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate, 'E') == 'Thu',
pyspark.sql.functions.date_sub(reg.AccountCreationDate, 3)).otherwise(
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate, 'E') == 'Fri',
pyspark.sql.functions.date_sub(reg.AccountCreationDate, 4)).otherwise(
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate, 'E') == 'Sat',
pyspark.sql.functions.date_sub(reg.AccountCreationDate, 5)).otherwise(
pyspark.sql.functions.when(pyspark.sql.functions.date_format(reg.AccountCreationDate, 'E') == 'Sun',
pyspark.sql.functions.date_sub(reg.AccountCreationDate, 6))
)))))))
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但是,对于应该相当简单的事情来说,这似乎是很多代码.这样做有更简洁的方法吗?