Using Pyspark i found how to replace nulls (' ') with string, but it fills all the cells of the dataframe with this string between the letters. Maybe the system sees nulls (' ') between the letters of the strings of the non empty cells.
These are the values of the initial dataframe:
+-----------------+-----+
|CustomerRelStatus|count|
+-----------------+-----+
| Ανοιχτος | 477|
| Κλειστος | 68|
| 'γνωστο | 291|
| | 1165|
+-----------------+-----+
After using this:
newDf = df.withColumn('CustomerStatus', regexp_replace('CustomerRelStatus', '', '-1000'))
it returns:
+--------------------+-----+
| CustomerRelStatus |count|
+--------------------+-----+
|-1000Α-1000ν-1000...| 477|
|-1000Κ-1000λ-1000...| 68|
|-1000ʼ-1000γ-1000...| 291|
| -1000| 1165|
+--------------------+-----+
Is there any other way?
Hope this helps!
from pyspark.sql.functions import col, when
#sample data
df = sc.parallelize([['abc', '123'],
['efg', '456'],
['', '789']]).toDF(('CustomerRelStatus', 'count'))
#replace empty string with 'null' and then impute missing value, OR directly impute it with '-1000' in 'otherwise' condition
df = df.withColumn("CustomerStatus",
when(col('CustomerRelStatus') != '', col('CustomerRelStatus')).otherwise(None)).drop('CustomerRelStatus')
df = df.na.fill({'CustomerStatus': '-1000'})
df.show()
Output is
+-----+--------------+
|count|CustomerStatus|
+-----+--------------+
| 123| abc|
| 456| efg|
| 789| -1000|
+-----+--------------+
Don't forget to let us know if it solved your problem :)
I think you are missing a space in the second argument of regexp_replace so maybe try this:
newDf = df.withColumn('CustomerStatus', regexp_replace('CustomerRelStatus', ' ', '-1000'))
Related
I'm trying to split and then combine 2 DataFrame columns into 1, with another column identifying which column it originated from. Here is the code to generate the sample DF
val data = Seq(("1", "in1,in2,in3", null), ("2","in4,in5","ex1,ex2,ex3"), ("3", null, "ex4,ex5"), ("4", null, null))
val df = spark.sparkContext.parallelize(data).toDF("id", "include", "exclude")
This is the sample DF
+---+-----------+-----------+
| id| include| exclude|
+---+-----------+-----------+
| 1|in1,in2,in3| null|
| 2| in4,in5|ex1,ex2,ex3|
| 3| null| ex4,ex5|
| 4| null| null|
+---+-----------+-----------+
which I'm trying to transform into
+---+----+---+
| id|type|col|
+---+----+---+
| 1|incl|in1|
| 1|incl|in2|
| 1|incl|in3|
| 2|incl|in4|
| 2|incl|in5|
| 2|excl|ex1|
| 2|excl|ex2|
| 2|excl|ex3|
| 3|excl|ex4|
| 3|excl|ex5|
+---+----+---+
EDIT: Should mention that the data inside each of the cells in the example DF is just for visualization, and doesn't need to have the form in1,ex1, etc.
I can get it to work with union, as so:
df.select($"id", lit("incl").as("type"), explode(split(col("include"), ",")))
.union(
df.select($"id", lit("excl").as("type"), explode(split(col("exclude"), ",")))
)
but I was wondering if this was possible to do without using union.
The approach that I am thinking off is, better club both the include and exclude columns and then apply explode function. Then fetch only the column which doesn't have nulls. Finally a case statement.
This might be a long process.
With cte as ( select id, include+exclude as outputcol from SQL),
Ctes as (select id,explode(split(col("outputcol"), ",")) as finalcol from cte)
Select id, case when finalcol like 'in%' then 'incl' else 'excl' end as type, finalcol from Ctes
Where finalcol is not null
I'm new to Pyspark and trying to transform data
Given dataframe
Col1
A=id1a A=id2a B=id1b C=id1c B=id2b
D=id1d A=id3a B=id3b C=id2c
A=id4a C=id3c
Required:
A B C
id1a id1b id1c
id2a id2b id2c
id3a id3b id3b
id4a null null
I have tried pivot, but that gives first value.
There might be a better way , however an approach is splitting the column on spaces to create array of the entries and then using higher order functions(spark 2.4+) to split on the '=' for each entry in the splitted array .Then explode and create 2 columns one with the id and one with the value. Then we can assign a row number to each partition and groupby then pivot:
import pyspark.sql.functions as F
df1 = (df.withColumn("Col1",F.split(F.col("Col1"),"\s+")).withColumn("Col1",
F.explode(F.expr("transform(Col1,x->split(x,'='))")))
.select(F.col("Col1")[0].alias("cols"),F.col("Col1")[1].alias("vals")))
from pyspark.sql import Window
w = Window.partitionBy("cols").orderBy("cols")
final = (df1.withColumn("Rnum",F.row_number().over(w)).groupBy("Rnum")
.pivot("cols").agg(F.first("vals")).orderBy("Rnum"))
final.show()
+----+----+----+----+----+
|Rnum| A| B| C| D|
+----+----+----+----+----+
| 1|id1a|id1b|id1c|id1d|
| 2|id2a|id2b|id2c|null|
| 3|id3a|id3b|id3c|null|
| 4|id4a|null|null|null|
+----+----+----+----+----+
this is how df1 looks like after the transformation:
df1.show()
+----+----+
|cols|vals|
+----+----+
| A|id1a|
| A|id2a|
| B|id1b|
| C|id1c|
| B|id2b|
| D|id1d|
| A|id3a|
| B|id3b|
| C|id2c|
| A|id4a|
| C|id3c|
+----+----+
May be I don't know the full picture, but the data format seems to be strange. If nothing can be done at the data source, then some collects, pivots and joins will be needed. Try this.
import pyspark.sql.functions as F
test = sqlContext.createDataFrame([('A=id1a A=id2a B=id1b C=id1c B=id2b',1),('D=id1d A=id3a B=id3b C=id2c',2),('A=id4a C=id3c',3)],schema=['col1','id'])
tst_spl = test.withColumn("item",(F.split('col1'," ")))
tst_xpl = tst_spl.select(F.explode("item"))
tst_map = tst_xpl.withColumn("key",F.split('col','=')[0]).withColumn("value",F.split('col','=')[1]).drop('col')
#%%
tst_pivot = tst_map.groupby(F.lit(1)).pivot('key').agg(F.collect_list(('value'))).drop('1')
#%%
tst_arr = [tst_pivot.select(F.posexplode(coln)).withColumnRenamed('col',coln) for coln in tst_pivot.columns]
tst_fin = reduce(lambda df1,df2:df1.join(df2,on='pos',how='full'),tst_arr).orderBy('pos')
tst_fin.show()
+---+----+----+----+----+
|pos| A| B| C| D|
+---+----+----+----+----+
| 0|id3a|id3b|id1c|id1d|
| 1|id4a|id1b|id2c|null|
| 2|id1a|id2b|id3c|null|
| 3|id2a|null|null|null|
+---+----+----+----+----
In pyspark how can i use expr to check whether a whole column contains the value in columnA of that row.
pseudo code below
df=df.withColumn("Result", expr(if any the rows in column1 contains the value colA (for this row) then 1 else 0))
Take an arbitrary example:
valuesCol = [('rose','rose is red'),('jasmine','I never saw Jasmine'),('lily','Lili dont be silly'),('daffodil','what a flower')]
df = sqlContext.createDataFrame(valuesCol,['columnA','columnB'])
df.show()
+--------+-------------------+
| columnA| columnB|
+--------+-------------------+
| rose| rose is red|
| jasmine|I never saw Jasmine|
| lily| Lili dont be silly|
|daffodil| what a flower|
+--------+-------------------+
Application of expr() here. How one can use expr(), just look for the corresponding SQL syntax and it should work with expr() mostly.
df = df.withColumn('columnA_exists',expr("(case when instr(lower(columnB), lower(columnA))>=1 then 1 else 0 end)"))
df.show()
+--------+-------------------+--------------+
| columnA| columnB|columnA_exists|
+--------+-------------------+--------------+
| rose| rose is red| 1|
| jasmine|I never saw Jasmine| 1|
| lily| Lili dont be silly| 0|
|daffodil| what a flower| 0|
+--------+-------------------+--------------+
I am having trouble splitting my data-frame column into two rows based on a hyphen delimiter.
from pyspark.mllib.linalg.distributed import IndexedRow
rows = sc.parallelize([['14-banana'], ['12-cheese'], ['13-olives'], ['11-almonds']])
rows_df = rows.toDF(["ID"])
rows_df.show()
+----------+
| ID|
+----------+
| 14-banana|
| 12-cheese|
| 13-olives|
|11-almonds|
+----------+
So I want two columns one for ID in numeric and one for the food type as a string.
You are looking for the split function. Please find example below:
import pyspark.sql.functions as F
rows = sc.parallelize([['14-banana'], ['12-cheese'], ['13-olives'], ['11-almonds']])
rows_df = rows.toDF(["ID"])
split = F.split(rows_df.ID, '-')
rows_df = rows_df.withColumn('number', split.getItem(0))
rows_df = rows_df.withColumn('fruit', split.getItem(1))
rows_df.show()
Output:
+----------+------+-------+
| ID|number| fruit|
+----------+------+-------+
| 14-banana| 14| banana|
| 12-cheese| 12| cheese|
| 13-olives| 13| olives|
|11-almonds| 11|almonds|
+----------+------+-------+
Is there any way to transpose dataframe rows into columns.
I have following structure as a input:
val inputDF = Seq(("pid1","enc1", "bat"),
("pid1","enc2", ""),
("pid1","enc3", ""),
("pid3","enc1", "cat"),
("pid3","enc2", "")
).toDF("MemberID", "EncounterID", "entry" )
inputDF.show:
+--------+-----------+-----+
|MemberID|EncounterID|entry|
+--------+-----------+-----+
| pid1| enc1| bat|
| pid1| enc2| |
| pid1| enc3| |
| pid3| enc1| cat|
| pid3| enc2| |
+--------+-----------+-----+
expected result:
+--------+----------+----------+----------+-----+
|MemberID|Encounter1|Encounter2|Encounter3|entry|
+--------+----------+----------+----------+-----+
| pid1| enc1| enc2| enc3| bat|
| pid3| enc1| enc2| null| cat|
+--------+----------+----------+----------+-----+
Please suggest if there is any optimized direct API available for transposing rows into columns.
my input data size is quite huge, so actions like collect, I wont be able to perform as it would take all the data on driver.
I am using Spark 2.x
I am not sure that what you need is what you actually asked. Yet, just in case here is an idea:
val entries = inputDF.where('entry isNotNull)
.where('entry !== "")
.select("MemberID", "entry").distinct
val df = inputDF.groupBy("MemberID")
.agg(collect_list("EncounterID") as "encounterList")
.join(entries, Seq("MemberID"))
df.show
+--------+-------------------------+-----+
|MemberID| encounterList |entry|
+--------+-------------------------+-----+
| pid1| [enc2, enc1, enc3]| bat|
| pid3| [enc2, enc1]| cat|
+--------+-------------------------+-----+
The order of the list is not deterministic but you may sort it and then extract new columns from it with .withColumn("Encounter1", sort_array($"encounterList")(0))...
Other idea
In case what you want is to put the value of entry in the corresponding "Encounter" column, you can use a pivot:
inputDF
.groupBy("MemberID")
.pivot("EncounterID", Seq("enc1", "enc2", "enc3"))
.agg(first("entry")).show
+--------+----+----+----+
|MemberID|enc1|enc2|enc3|
+--------+----+----+----+
| pid1| bat| | |
| pid3| cat| | |
+--------+----+----+----+
Adding Seq("enc1", "enc2", "enc3") is optionnal but since you know the content of the column, it will speed up the computation.