[英]pyspark udf for mutils columns
我有一個數據框
import pandas as pd
ndf = pd.DataFrame({'a':[False, False,True,True,False], 'b':[False, False,False,False, True]})
ndf_s = sqlContext.createDataFrame(ndf)
我想獲得一個名為“ action”的新列。 它可以包含兩個值,如果ndf ['a']為True,則“動作”的值為“我是a”,如果ndf ['b']為True,則“動作”的值為“我是b”。 。 否則獲取值None。 如果兩列都為真,則返回值為“我是a和b”。換句話說,我想獲取一個DataFrame為:
ndf_result = sqlContext.createDataFrame(pd.DataFrame({'a':[False, False,True,True,False], 'b':[False, False,False,False, True], 'action':[None, None, 'I am a', 'I am a', 'I am b']}))
您可以使用when.otherwise
:
import pyspark.sql.functions as F
ndf_s.withColumn("action", F.when(
ndf_s["a"] & ndf_s["b"], "I am a and b"
).otherwise(
F.when(
ndf_s["a"], "I am a"
).otherwise(
F.when(ndf_s["b"], "I am b")
)
)
).show()
+-----+-----+------------+
| a| b| action|
+-----+-----+------------+
| true| true|I am a and b|
|false|false| null|
| true|false| I am a|
| true|false| I am a|
|false| true| I am b|
+-----+-----+------------+
udf
另一個選擇:
import pyspark.sql.functions as F
@F.udf
def action(col_a, col_b):
if col_a and col_b:
return "I am a and b"
elif col_a:
return "I am a"
elif col_b:
return "I am b"
ndf_s.withColumn("action", action(ndf_s["a"], ndf_s["b"])).show()
+-----+-----+------------+
| a| b| action|
+-----+-----+------------+
| true| true|I am a and b|
|false|false| null|
| true|false| I am a|
| true|false| I am a|
|false| true| I am b|
+-----+-----+------------+
import pyspark.sql.functions as udf
import pandas as pd
ndf = pd.DataFrame({'a':[False, False,True,True,False], 'b':[False, False,False,False, True]})
ndf_s = sqlContext.createDataFrame(ndf)
def get_expected_string(a,b):
if a and b:
return "I am a and b"
elif a:
return "I am a"
elif b:
return "I am b"
else: return None
# defining udf function for get_expected_string
get_expected_string_udf = udf(get_expected_string, StringType())
ndf_s = ndf_s.withColumn("action",get_expected_string_udf("a","b"))
ndf_s.show()
+-----+-----+------------+
| a| b| action|
+-----+-----+------------+
| true| true|I am a and b|
|false|false| null|
| true|false| I am a|
| true|false| I am a|
|false| true| I am b|
+-----+-----+------------+
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