transform distinct row values to different columns with corresponding rows using Pyspark - pyspark

Question

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.

Answer 1

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|
+----+----+

Answer 2

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|
+---+----+----+----+----