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pyspark给dataframe增加新的一列的实现示例

作者:晓东邪

这篇文章主要介绍了pyspark给dataframe增加新的一列的实现示例,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友们下面随着小编来一起学习学习吧

熟悉pandas的pythoner 应该知道给dataframe增加一列很容易,直接以字典形式指定就好了,pyspark中就不同了,摸索了一下,可以使用如下方式增加

from pyspark import SparkContext
from pyspark import SparkConf
from pypsark.sql import SparkSession
from pyspark.sql import functions

spark = SparkSession.builder.config(conf=SparkConf()).getOrCreate()

data =   [['Alice', 19, 'blue', '["Alice", 19, "blue"]'],
  ['Jane', 20, 'green', '["Jane", 20, "green"]'],
   ['Mary', 21, 'blue', '["Mary", 21, "blue"]'], ]
frame = spark.createDataFrame(data, schema=["name", "age", "eye_color", "detail"])

frame.cache()
frame.show()

+-----+---+---------+--------------------+
| name|age|eye_color|              detail|
+-----+---+---------+--------------------+
|Alice| 19|     blue|["Alice", 19, "bl...|
| Jane| 20|    green|["Jane", 20, "gre...|
| Mary| 21|     blue|["Mary", 21, "blue"]|
+-----+---+---------+--------------------+

1、 增加常数项

frame2 = frame.withColumn("contant", functions.lit(10))
frame2.show()

+-----+---+---------+--------------------+-------+
| name|age|eye_color|              detail|contant|
+-----+---+---------+--------------------+-------+
|Alice| 19|     blue|["Alice", 19, "bl...|     10|
| Jane| 20|    green|["Jane", 20, "gre...|     10|
| Mary| 21|     blue|["Mary", 21, "blue"]|     10|
+-----+---+---------+--------------------+-------+

2、简单根据某列进行计算

2.1 使用 withColumn

frame3_1 = frame.withColumn("name_length", functions.length(frame.name))
frame3_1.show()

+-----+---+---------+--------------------+-----------+
| name|age|eye_color|              detail|name_length|
+-----+---+---------+--------------------+-----------+
|Alice| 19|     blue|["Alice", 19, "bl...|          5|
| Jane| 20|    green|["Jane", 20, "gre...|          4|
| Mary| 21|     blue|["Mary", 21, "blue"]|          4|
+-----+---+---------+--------------------+-----------+

2.2 使用 select

frame3_2 = frame.select(["name", functions.length(frame.name).alias("name_length")])
frame3_2.show()

+-----+-----------+
| name|name_length|
+-----+-----------+
|Alice|          5|
| Jane|          4|
| Mary|          4|
+-----+-----------+

2.3 使用 selectExpr

frame3_3 = frame.selectExpr(["name", "length(name) as name_length"])
frame3_3.show()

+-----+-----------+
| name|name_length|
+-----+-----------+
|Alice|          5|
| Jane|          4|
| Mary|          4|
+-----+-----------+

3、定制化根据某列进行计算

比如我想对某列做指定操作,但是对应的函数没得咋办,造,自己造~

frame4 = frame.withColumn("detail_length", functions.UserDefinedFunction(lambda obj: len(json.loads(obj)))(frame.detail))

# or
def length_detail(obj):
 return len(json.loads(obj))
frame4 = frame.withColumn("detail_length", functions.UserDefinedFunction(length_detail)(frame.detail))
frame4.show()

+-----+---+---------+--------------------+-------------+
| name|age|eye_color|              detail|detail_length|
+-----+---+---------+--------------------+-------------+
|Alice| 19|     blue|["Alice", 19, "bl...|            3|
| Jane| 20|    green|["Jane", 20, "gre...|            3|
| Mary| 21|     blue|["Mary", 21, "blue"]|            3|
+-----+---+---------+--------------------+-------------+

到此这篇关于pyspark给dataframe增加新的一列的实现示例的文章就介绍到这了,更多相关pyspark dataframe增加列内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

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