pyspark 数据类型转换_apache spark-将pyspark字符串转换为日期形式
apache spark-将pyspark字符串转换为日期形式
我有一个日期pyspark数据框，其中的字符串列格式为df.select(to_date(df.STRING_COLUMN).alias('new_date')).show()，并且我尝试将其转换为日期列。
我试过了：
df.select(to_date(df.STRING_COLUMN).alias('new_date')).show()
我得到一串空值。 有人可以帮忙吗？
6个解决方案
69 votes
可以(最好是？)在没有udf的情况下执行此操作：
from pyspark.sql.functions import unix_timestamp, from_unixtime
df = spark.createDataFrame(
[("11/25/1991",), ("11/24/1991",), ("11/30/1991",)],
['date_str']
)
df2 = df.select(
'date_str',
from_unixtime(unix_timestamp('date_str', 'MM/dd/yyy')).alias('date')
)
print(df2)
#DataFrame[date_str: string, date: timestamp]
df2.show(truncate=False)
#+----------+-------------------+
#|date_str |date |
#+----------+-------------------+
#|11/25/1991|1991-11-25 00:00:00|
#|11/24/1991|1991-11-24 00:00:00|
#|11/30/1991|1991-11-30 00:00:00|
#+----------+-------------------+
更新(1/10/2018)：
对于Spark 2.2+，最好的方法是使用format或format函数，它们都支持format参数。 从文档：
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_timestamp(df.t, 'yyyy-MM-dd HH:mm:ss').alias('dt')).collect()
[Row(dt=datetime.datetime(1997, 2, 28, 10, 30))]
santon answered 2020-01-02T13:17:32Z
37 votes
from datetime import datetime
from pyspark.sql.functions import col, udf
from pyspark.sql.types import DateType
# Creation of a dummy dataframe:
df1 = sqlContext.createDataFrame([("11/25/1991","11/24/1991","11/30/1991"),
("11/25/1391","11/24/1992","11/30/1992")], schema=['first', 'second', 'third'])
# Setting an user define function:
# This function converts the string cell into a date:
func = udf (lambda x: datetime.strptime(x, '%m/%d/%Y'), DateType())
df = df1.withColumn('test', func(col('first')))
df.show()
df.printSchema()
这是输出：
+----------+----------+----------+----------+
| first| second| third| test|
+----------+----------+----------+----------+
|11/25/1991|11/24/1991|11/30/1991|1991-01-25|
|11/25/1391|11/24/1992|11/30/1992|1391-01-17|
+----------+----------+----------+----------+
root
|-- first: string (nullable = true)
|-- second: string (nullable = true)
|-- third: string (nullable = true)
|-- test: date (nullable = true)
Hugo Reyes answered 2020-01-02T13:17:54Z
22 votes
strptime()方法对我不起作用。 我得到另一个更清洁的解决方案，使用演员：
from pyspark.sql.types import DateType
spark_df1 = spark_df.withColumn("record_date",spark_df['order_submitted_date'].cast(DateType()))
#below is the result
spark_df1.select('order_submitted_date','record_date').show(10,False)
+---------------------+-----------+
|order_submitted_date |record_date|
+---------------------+-----------+
|2015-08-19 12:54:16.0|2015-08-19 |
|2016-04-14 13:55:50.0|2016-04-14 |
|2013-10-11 18:23:36.0|2013-10-11 |
|2015-08-19 20:18:55.0|2015-08-19 |
|2015-08-20 12:07:40.0|2015-08-20 |
|2013-10-11 21:24:12.0|2013-10-11 |
|2013-10-11 23:29:28.0|2013-10-11 |
|2015-08-20 16:59:35.0|2015-08-20 |
|2015-08-20 17:32:03.0|2015-08-20 |
|2016-04-13 16:56:21.0|2016-04-13 |
Frank answered 2020-01-02T13:18:14Z
7 votes
在接受的答案更新中，您没有看到to_date函数的示例，因此使用该函数的另一种解决方案是：
from pyspark.sql import functions as F
df = df.withColumn(
'new_date',
F.to_date(
F.unix_timestamp('STRINGCOLUMN', 'MM-dd-yyyy').cast('timestamp'))
Manrique answered 2020-01-02T13:18:35Z
1 votes
尝试这个：
df = spark.createDataFrame([('2018-07-27 10:30:00',)], ['Date_col'])
df.select(from_unixtime(unix_timestamp(df.Date_col, 'yyyy-MM-dd HH:mm:ss')).alias('dt_col'))
df.show()
+-------------------+
| Date_col|
+-------------------+
|2018-07-27 10:30:00|
+-------------------+
Vishwajeet Pol answered 2020-01-02T13:18:55Z
1 votes
可能没有那么多答案，所以想分享我的代码，这可以帮助某人
from pyspark.sql import SparkSession
from pyspark.sql.functions import to_date
spark = SparkSession.builder.appName("Python Spark SQL basic example")\
.config("spark.some.config.option", "some-value").getOrCreate()
df = spark.createDataFrame([('2019-06-22',)], ['t'])
df1 = df.select(to_date(df.t, 'yyyy-MM-dd').alias('dt'))
print df1
print df1.show()
输出
DataFrame[dt: date]
+----------+
| dt|
+----------+
|2019-06-22|
+----------+
如果要转换日期时间，则将上述代码转换为日期，然后使用to_timestamp。如果您有任何疑问，请告诉我。
Santosh kumar Manda answered 2020-01-02T13:19:23Z