I have a dataframe as follows:
| created | id | date |value|
| 1650983874871 | x | 2020-05-08 | 5 |
| 1650367659030 | x | 2020-05-08 | 3 |
| 1639429213087 | x | 2020-05-08 | 2 |
| 1650983874871 | x | 2020-06-08 | 5 |
| 1650367659030 | x | 2020-06-08 | 3 |
| 1639429213087 | x | 2020-06-08 | 2 |
I want to get max of created for every date.
The table should look like :
| created | id | date |value|
| 1650983874871 | x | 2020-05-08 | 5 |
| 1650983874871 | x | 2020-06-08 | 5 |
I tried:
df2 = (
df
.groupby(['id', 'date'])
.agg(
F.max(F.col('created')).alias('created_max')
)
df3 = df.join(df2, on=['id', 'date'], how='left')
But this is not working as expected.
Can anyone help me.
You need to make two changes.
The join condition needs to include created as well. Here I have changed alias to alias("created") to make the join easier. This will ensure a unique join condition (if there are no duplicate created values).
The join type must be inner.
df2 = (
df
.groupby(['id', 'date'])
.agg(
F.max(F.col('created')).alias('created')
)
)
df3 = df.join(df2, on=['id', 'date','created'], how='inner')
df3.show()
+---+----------+-------------+-----+
| id| date| created|value|
+---+----------+-------------+-----+
| x|2020-05-08|1650983874871| 5|
| x|2020-06-08|1650983874871| 5|
+---+----------+-------------+-----+
Instead of using the group by and joining, you can also use the Window in pyspark.sql:
from pyspark.sql import functions as func
from pyspark.sql.window import Window
df = df\
.withColumn('max_created', func.max('created').over(Window.partitionBy('date', 'id')))\
.filter(func.col('created')==func.col('max_created'))\
.drop('max_created')
Step:
Get the max value based on the Window
Filter the row by using the matched timestamp
Related
I have a sample dataframe:
df = spark.createDataFrame([('name1','id1',1,None,3),('name2','id2',None,2,5)],['NAME','personID','col1','col2','col3'])
My use case has 15 columns
What I would like to do is using case when and loop, to add new columns that correspond to each column from the original except the first two columns. Within those new columns, it will give a value of 1 if notNull, otherwise 0.
I am aiming to get something like below:
+--------+--------+--------+-------+-------+-------+------+------+
|Name | ID | col1 | col2 | col3 | col1_N|col2_N|col3_N|
+--------+--------+--------+-------+-------+-------+------+------+
|name1 | id1 | 1 | Null | 3 | 1 | 0 | 1 |
|name2 | id2 | Null | 2 | 5 | 0 | 1 | 1 |
+--------+--------+--------+-------+-------+-------+------+------+
the first five columns are the original columns, the last three columns will be added with corresponding 1 or 0 from 'col1', 'col2', and 'col3' values.
The last code/s I am working on creates a new one but does not keep the original dataframe values.
df.select([when(col(c).isNotNull(), 1).otherwise(0).alias(c + '_N') for c in df.columns])
for which I get:
+-------+-------+-------+------+------+
| Name_N| ID_N | col1_N|col2_N|col3_N|
+-------+-------+-------+------+------+
| 1 | 1 | 1 | 0 | 1 |
| 1 | 1 | 0 | 1 | 1 |
+-------+-------+-------+------+------+
The above could have been acceptable but I need to keep the original values of Name and ID columns.
I got an InvalidArgument with below:
df.select(['*'],[when(col(c).isNotNull(), 1).otherwise(0).alias(c + '_N') for c in df.columns])
TypeError: Invalid argument, not a string or column: ['*'] of type <class 'list'>. For column literals, use 'lit', 'array', 'struct' or 'create_map' function.
I thought selecting all first will give me all the columns of the original
UPDATE:
somehow this worked, but I only get the last column:
for c in df.columns[2:]:
sdf = df.withColumn(c+'_N', when(col(c).isNotNull(),1).otherwise(0))
but this is what I get:
+--------+--------+--------+-------+-------+------+
|Name | ID | col1 | col2 | col3 |col3_N|
+--------+--------+--------+-------+-------+------+
|name1 | id1 | 1 | Null | 3 | 1 |
|name2 | id2 | Null | 2 | 5 | 1 |
+--------+--------+--------+-------+-------+------+
``
I only got the last original column
Using list comprehension as show below will give expected result.
df.select([col(c) if c in ['NAME', 'personID'] else when(col(c).isNotNull(), 1).otherwise(0).alias(f"{c}_N") for c in df.columns]).show()
+-----+--------+------+------+------+
| NAME|personID|col1_N|col2_N|col3_N|
+-----+--------+------+------+------+
|name1| id1| 1| 0| 1|
|name2| id2| 0| 1| 1|
+-----+--------+------+------+------+
Just fix your 1st approach with specifying a slice of columns and simplify boolean condition:
df.select([col(c).isNotNull().cast("integer").alias(c + '_N') for c in df.columns[2:]])
I have two dataframes.
Df1
Id | Name | Remarks
---------------------
1 | A | Not bad
1 | B | Good
2 | C | Very bad
Df2
Id | Name | Place |Job
-----------------------
1 | A | Can | IT
2 |C | Cbe | CS
4 |L | anc | ME
5 | A | cne | IE
Output
Id | Name | Remarks |Results
------------------------------
1 | A | Not bad |True
1 | B | Good |False
2 | C | VeryGood |True
That is the result should be true if same id and name are present in both dataframes. I tried
df1['Results']=np.where(Df1['id','Name'].isin(Df2['Id','Name']),'true','false')
But it was not successful.
Use DataFrame.merge with indicator parameter and compare both values:
df = Df1[['id','Name']].merge(Df2[['Id','Name']], indicator='Results', how='left')
df['Results'] = df['Results'].eq('both')
Your solution is possible by compare index values by DataFrame.set_index with Index.isin:
df1['Results']= Df1.set_index(['id','Name']).index.isin(Df2.set_index(['id','Name']).index)
Or compare tuples from both columns:
df1['Results']= Df1[['id','Name']].agg(tuple, 1).isin(Df2[['id','Name']].agg(tuple, 1))
You can easily achieve by merge like #jezrael 's answer.
You can also achieve it with np.where,list comprehension and zip like below:
df1['Results']=np.where([str(i)+'_'+str(j)==str(k)+'_'+str(l) for i,j,k,l in zip(Df1['ID'],Df1['Name'],Df2['ID'],Df2['Name'])],True,False)
I have a need to be able to add new rows to a PySpark df will values based upon the contents of other rows with a common id. There will eventually millions of ids with lots rows for each id. I have tried the below method which works but seems overly complicated.
I start with a df in the format below (but in reality have more columns):
+-------+----------+-------+
| id | variable | value |
+-------+----------+-------+
| 1 | varA | 30 |
| 1 | varB | 1 |
| 1 | varC | -9 |
+-------+----------+-------+
Currently I am pivoting this df to get it in the following format:
+-----+------+------+------+
| id | varA | varB | varC |
+-----+------+------+------+
| 1 | 30 | 1 | -9 |
+-----+------+------+------+
On this df I can then use the standard withColumn and when functionality to add new columns based on the values in other columns. For example:
df = df.withColumn("varD", when((col("varA") > 16) & (col("varC") != -9)), 2).otherwise(1)
Which leads to:
+-----+------+------+------+------+
| id | varA | varB | varC | varD |
+-----+------+------+------+------+
| 1 | 30 | 1 | -9 | 1 |
+-----+------+------+------+------+
I can then pivot this df back to the original format leading to this:
+-------+----------+-------+
| id | variable | value |
+-------+----------+-------+
| 1 | varA | 30 |
| 1 | varB | 1 |
| 1 | varC | -9 |
| 1 | varD | 1 |
+-------+----------+-------+
This works but seems like it could, with millions of rows, lead to expensive and unnecessary operations. It feels like it should be doable without the need to pivot and unpivot the data. Do I need to do this?
I have read about Window functions and it sounds as if they may be another way to achieve the same result but to be honest I am struggling to get started with them. I can see how they can be used to generate a value, say a sum, for each id, or to find a maximum value but have not found a way to even get started on applying complex conditions that lead to a new row.
Any help to get started with this problem would be gratefully received.
You can use pandas_udf for adding/deleting rows/col on grouped data, and implement your processing logic in pandas udf.
import pyspark.sql.functions as F
row_schema = StructType(
[StructField("id", IntegerType(), True),
StructField("variable", StringType(), True),
StructField("value", IntegerType(), True)]
)
#F.pandas_udf(row_schema, F.PandasUDFType.GROUPED_MAP)
def addRow(pdf):
val = 1
if (len(pdf.loc[(pdf['variable'] == 'varA') & (pdf['value'] > 16)]) > 0 ) & \
(len(pdf.loc[(pdf['variable'] == 'varC') & (pdf['value'] != -9)]) > 0):
val = 2
return pdf.append(pd.Series([1, 'varD', val], index=['id', 'variable', 'value']), ignore_index=True)
df = spark.createDataFrame([[1, 'varA', 30],
[1, 'varB', 1],
[1, 'varC', -9]
], schema=['id', 'variable', 'value'])
df.groupBy("id").apply(addRow).show()
which resuts
+---+--------+-----+
| id|variable|value|
+---+--------+-----+
| 1| varA| 30|
| 1| varB| 1|
| 1| varC| -9|
| 1| varD| 1|
+---+--------+-----+
I want to get the distinct values and their respective counts of every column of a dataframe and store them as (k,v) in another dataframe.
Note: My Columns are not static, they keep changing. So, I cannot hardcore the column names instead I should loop through them.
For Example, below is my dataframe
+----------------+-----------+------------+
|name |country |DOB |
+----------------+-----------+------------+
| Blaze | IND| 19950312|
| Scarlet | USA| 19950313|
| Jonas | CAD| 19950312|
| Blaze | USA| 19950312|
| Jonas | CAD| 19950312|
| mark | USA| 19950313|
| mark | CAD| 19950313|
| Smith | USA| 19950313|
| mark | UK | 19950313|
| scarlet | CAD| 19950313|
My final result should be created in a new dataframe as (k,v) where k is the distinct record and v is the count of it.
+----------------+-----------+------------+
|name |country |DOB |
+----------------+-----------+------------+
| (Blaze,2) | (IND,1) |(19950312,3)|
| (Scarlet,2) | (USA,4) |(19950313,6)|
| (Jonas,3) | (CAD,4) | |
| (mark,3) | (UK,1) | |
| (smith,1) | | |
Can anyone please help me with this, I'm using Spark 2.4.0 and Scala 2.11.12
Note: My columns are dynamic, so I can't hardcore the columns and do groupby on them.
I don't have exact solution to your query but I can surely provide you with some help that can get you started working on your issue.
Create dataframe
scala> val df = Seq(("Blaze ","IND","19950312"),
| ("Scarlet","USA","19950313"),
| ("Jonas ","CAD","19950312"),
| ("Blaze ","USA","19950312"),
| ("Jonas ","CAD","19950312"),
| ("mark ","USA","19950313"),
| ("mark ","CAD","19950313"),
| ("Smith ","USA","19950313"),
| ("mark ","UK ","19950313"),
| ("scarlet","CAD","19950313")).toDF("name", "country","dob")
Next calculate count of distinct element of each column
scala> val distCount = df.columns.map(c => df.groupBy(c).count)
Create a range to iterate over distCount
scala> val range = Range(0,distCount.size)
range: scala.collection.immutable.Range = Range(0, 1, 2)
Aggregate your data
scala> val aggVal = range.toList.map(i => distCount(i).collect().mkString).toSeq
aggVal: scala.collection.immutable.Seq[String] = List([Jonas ,2][Smith ,1][Scarlet,1][scarlet,1][mark ,3][Blaze ,2], [CAD,4][USA,4][IND,1][UK ,1], [19950313,6][19950312,4])
Create data frame:
scala> Seq((aggVal(0),aggVal(1),aggVal(2))).toDF("name", "country","dob").show()
+--------------------+--------------------+--------------------+
| name| country| dob|
+--------------------+--------------------+--------------------+
|[Jonas ,2][Smith...|[CAD,4][USA,4][IN...|[19950313,6][1995...|
+--------------------+--------------------+--------------------+
I hope this helps you in some way.
If I have this events dataframe df_e below:
|------|------------|-------|
| group| event date | count |
| x123 | 2016-01-06 | 1 |
| | 2016-01-08 | 10 |
| | 2016-02-15 | 9 |
| | 2016-05-22 | 6 |
| | 2016-05-29 | 2 |
| | 2016-05-31 | 6 |
| | 2016-12-29 | 1 |
| x124 | 2016-01-01 | 1 |
...
and also know the t0 which is the beginning of time (let's say for x123 it's 2016-01-01) and tN which is the end of experiment from another dataframe df_s (2017-05-25), then how can I create the dataframe df_new which should like this
|------|------------|---------------|--------|
| group| obs. weekly| lifetime, week| status |
| x123 | 2016-01-01 | 1 | 1 |
| | 2016-01-08 | 0 | 0 |
| | 2016-01-15 | 0 | 0 |
| | 2016-01-22 | 1 | 1 |
| | 2016-01-29 | 2 | 1 |
...
| | 2017-05-18 | 1 | 1 |
| | 2017-05-25 | 1 | 1 |
...
| x124 | 2017-05-18 | 1 | 1 |
| x124 | 2017-05-25 | 1 | 1 |
Explanation: take t0 and generate rows until tN per week period. For each row R, search with that group if the event date falls within R, if True, then count how long in weeks it lives there, also set status = 1 as alive, otherwise set lifetime, status columns for this R as 0, e.g. dead.
Questions:
1) How to generate dataframes per group given t0 and tN values, e.g. generate [group, obs. weekly, lifetime, status] columns for (tN - t0) / week rows?
2) How to accomplish the construction of such df_new dataframe explained above?
I can begin with this so far =)
import pandas as pd
# 1. generate dataframes per group to get the boundary within `t0` and `tN` from df_s dataframe, where each dataframe has "group, obs, lifetime, status" columns X (tN - t0 / week) rows filled with 0 values.
df_all = pd.concat([df_group1, df_group2])
def do_that(R):
found_event_row = df_e.iloc[[R.group]]
# check if found_event_row['date'] falls into R['obs'] week
# if True, then found how long it's there
df_new = df_all.apply(do_that)
I'm not really sure if I get you but group one is not related to group two, right? if that's the case I think what you want is something like this:
import pandas as pd
df_group1 = df_group1.set_index('event date')
df_group1.index = pd.to_datetime(df_group1.index) #convert the index to datetime so you can 'resample'
df_group1['lifetime, week'] = df_group1.resample('1W').apply(lamda x: yourfuncion(x))
df_group1 = df_group1.reset_index()
df_group1['status']= df_group1.apply(lambda x: 1 if x['lifetime, week']>0 else 0)
#do the same with group2 and concat to create df_all
I'm not sure how you get 'lifetime, week' but all that's left is creating the function that generates it.