Concaténer deux bases de données PySpark

Je suis en train de concaténer deux PySpark dataframes avec quelques colonnes qui ne sont que sur chacun d'eux:

from pyspark.sql.functions import randn, rand

df_1 = sqlContext.range(0, 10)

+--+
|id|
+--+
| 0|
| 1|
| 2|
| 3|
| 4|
| 5|
| 6|
| 7|
| 8|
| 9|
+--+

df_2 = sqlContext.range(11, 20)

+--+
|id|
+--+
| 10|
| 11|
| 12|
| 13|
| 14|
| 15|
| 16|
| 17|
| 18|
| 19|
+--+

df_1 = df_1.select("id", rand(seed=10).alias("uniform"), randn(seed=27).alias("normal"))
df_2 = df_2.select("id", rand(seed=10).alias("uniform"), randn(seed=27).alias("normal_2"))

et maintenant, je veux générer une troisième dataframe. Je voudrais quelque chose comme les pandas concat:

df_1.show()
+---+--------------------+--------------------+
| id|             uniform|              normal|
+---+--------------------+--------------------+
|  0|  0.8122802274304282|  1.2423430583597714|
|  1|  0.8642043127063618|  0.3900018344856156|
|  2|  0.8292577771850476|  1.8077401259195247|
|  3|   0.198558705368724| -0.4270585782850261|
|  4|0.012661361966674889|   0.702634599720141|
|  5|  0.8535692890157796|-0.42355804115129153|
|  6|  0.3723296190171911|  1.3789648582622995|
|  7|  0.9529794127670571| 0.16238718777444605|
|  8|  0.9746632635918108| 0.02448061333761742|
|  9|   0.513622008243935|  0.7626741803250845|
+---+--------------------+--------------------+
df_2.show()
+---+--------------------+--------------------+
| id|             uniform|            normal_2|
+---+--------------------+--------------------+
| 11|  0.3221262660507942|  1.0269298899109824|
| 12|  0.4030672316912547|   1.285648175568798|
| 13|  0.9690555459609131|-0.22986601831364423|
| 14|0.011913836266515876|  -0.678915153834693|
| 15|  0.9359607054250594|-0.16557488664743034|
| 16| 0.45680471157575453| -0.3885563551710555|
| 17|  0.6411908952297819|  0.9161177183227823|
| 18|  0.5669232696934479|  0.7270125277020573|
| 19|   0.513622008243935|  0.7626741803250845|
+---+--------------------+--------------------+
#do some concatenation here, how?
df_concat.show()
| id|             uniform|              normal| normal_2   |
+---+--------------------+--------------------+------------+
|  0|  0.8122802274304282|  1.2423430583597714| None       |
|  1|  0.8642043127063618|  0.3900018344856156| None       |
|  2|  0.8292577771850476|  1.8077401259195247| None       |
|  3|   0.198558705368724| -0.4270585782850261| None       |
|  4|0.012661361966674889|   0.702634599720141| None       |
|  5|  0.8535692890157796|-0.42355804115129153| None       |
|  6|  0.3723296190171911|  1.3789648582622995| None       |
|  7|  0.9529794127670571| 0.16238718777444605| None       |
|  8|  0.9746632635918108| 0.02448061333761742| None       |
|  9|   0.513622008243935|  0.7626741803250845| None       |
| 11|  0.3221262660507942|  None              | 0.123      |
| 12|  0.4030672316912547|  None              |0.12323     |
| 13|  0.9690555459609131|  None              |0.123       |
| 14|0.011913836266515876|  None              |0.18923     |
| 15|  0.9359607054250594|  None              |0.99123     |
| 16| 0.45680471157575453|  None              |0.123       |
| 17|  0.6411908952297819|  None              |1.123       |
| 18|  0.5669232696934479|  None              |0.10023     |
| 19|   0.513622008243935|  None              |0.916332123 |
+---+--------------------+--------------------+------------+

Est-ce possible?

source d'informationauteur Ivan

Peut-être que vous pouvez essayer de créer la non-existante colonnes et en appelant union (unionAll pour l'Étincelle de 1,6 ou moins):

cols = ['id', 'uniform', 'normal', 'normal_2']    
df_1_new = df_1.withColumn("normal_2", lit(None)).select(cols)
df_2_new = df_2.withColumn("normal", lit(None)).select(cols)
result = df_1_new.union(df_2_new)

16
```
df_concat = df_1.union(df_2)
```
La dataframes peut-être besoin d'avoir de colonnes identiques, dans ce cas vous pouvez utiliser withColumn() pour créer normal_1 et normal_2

Ici est une façon de le faire, dans le cas où il est toujours utile: j'ai couru ce dans pyspark shell, Python version 2.7.12 et mon Étincelle installer en était à la version 2.0.1.

PS: je suppose que vous vouliez dire à l'utilisation des graines différentes pour la df_1 df_2 et le code ci-dessous en témoigne.

from pyspark.sql.types import FloatType
from pyspark.sql.functions import randn, rand
import pyspark.sql.functions as F
df_1 = sqlContext.range(0, 10)
df_2 = sqlContext.range(11, 20)
df_1 = df_1.select("id", rand(seed=10).alias("uniform"), randn(seed=27).alias("normal"))
df_2 = df_2.select("id", rand(seed=11).alias("uniform"), randn(seed=28).alias("normal_2"))
def get_uniform(df1_uniform, df2_uniform):
if df1_uniform:
return df1_uniform
if df2_uniform:
return df2_uniform
u_get_uniform = F.udf(get_uniform, FloatType())
df_3 = df_1.join(df_2, on = "id", how = 'outer').select("id", u_get_uniform(df_1["uniform"], df_2["uniform"]).alias("uniform"), "normal", "normal_2").orderBy(F.col("id"))

Ici sont les résultats que j'obtiens:

df_1.show()
+---+-------------------+--------------------+
| id|            uniform|              normal|
+---+-------------------+--------------------+
|  0|0.41371264720975787|  0.5888539012978773|
|  1| 0.7311719281896606|  0.8645537008427937|
|  2| 0.1982919638208397| 0.06157382353970104|
|  3|0.12714181165849525|  0.3623040918178586|
|  4| 0.7604318153406678|-0.49575204523675975|
|  5|0.12030715258495939|  1.0854146699817222|
|  6|0.12131363910425985| -0.5284523629183004|
|  7|0.44292918521277047| -0.4798519469521663|
|  8| 0.8898784253886249| -0.8820294772950535|
|  9|0.03650707717266999| -2.1591956435415334|
+---+-------------------+--------------------+
df_2.show()
+---+-------------------+--------------------+
| id|            uniform|            normal_2|
+---+-------------------+--------------------+
| 11| 0.1982919638208397| 0.06157382353970104|
| 12|0.12714181165849525|  0.3623040918178586|
| 13|0.12030715258495939|  1.0854146699817222|
| 14|0.12131363910425985| -0.5284523629183004|
| 15|0.44292918521277047| -0.4798519469521663|
| 16| 0.8898784253886249| -0.8820294772950535|
| 17| 0.2731073068483362|-0.15116027592854422|
| 18| 0.7784518091224375| -0.3785563841011868|
| 19|0.43776394586845413| 0.47700719174464357|
+---+-------------------+--------------------+
df_3.show()
+---+-----------+--------------------+--------------------+                     
| id|    uniform|              normal|            normal_2|
+---+-----------+--------------------+--------------------+
|  0| 0.41371265|  0.5888539012978773|                null|
|  1|  0.7311719|  0.8645537008427937|                null|
|  2| 0.19829196| 0.06157382353970104|                null|
|  3| 0.12714182|  0.3623040918178586|                null|
|  4|  0.7604318|-0.49575204523675975|                null|
|  5|0.120307155|  1.0854146699817222|                null|
|  6| 0.12131364| -0.5284523629183004|                null|
|  7| 0.44292918| -0.4798519469521663|                null|
|  8| 0.88987845| -0.8820294772950535|                null|
|  9|0.036507078| -2.1591956435415334|                null|
| 11| 0.19829196|                null| 0.06157382353970104|
| 12| 0.12714182|                null|  0.3623040918178586|
| 13|0.120307155|                null|  1.0854146699817222|
| 14| 0.12131364|                null| -0.5284523629183004|
| 15| 0.44292918|                null| -0.4798519469521663|
| 16| 0.88987845|                null| -0.8820294772950535|
| 17| 0.27310732|                null|-0.15116027592854422|
| 18|  0.7784518|                null| -0.3785563841011868|
| 19| 0.43776396|                null| 0.47700719174464357|
+---+-----------+--------------------+--------------------+

Réponses ci-dessus sont très élégantes. J'ai écrit cette fonction depuis longtemps de retour où j'ai également du mal à concaténer deux dataframe avec des colonnes distinctes.

Supposons que vous avez dataframe sdf1 et sdf2

from pyspark.sql import functions as F
from pyspark.sql.types import *
def unequal_union_sdf(sdf1, sdf2):
s_df1_schema = set((x.name, x.dataType) for x in sdf1.schema)
s_df2_schema = set((x.name, x.dataType) for x in sdf2.schema)
for i,j in s_df2_schema.difference(s_df1_schema):
sdf1 = sdf1.withColumn(i,F.lit(None).cast(j))
for i,j in s_df1_schema.difference(s_df2_schema):
sdf2 = sdf2.withColumn(i,F.lit(None).cast(j))
common_schema_colnames = sdf1.columns
sdk = \
sdf1.select(common_schema_colnames).union(sdf2.select(common_schema_colnames))
return sdk 
sdf_concat = unequal_union_sdf(sdf1, sdf2)

Cela devrait le faire pour vous ...

from pyspark.sql.types import FloatType
from pyspark.sql.functions import randn, rand, lit, coalesce, col
import pyspark.sql.functions as F
df_1 = sqlContext.range(0, 6)
df_2 = sqlContext.range(3, 10)
df_1 = df_1.select("id", lit("old").alias("source"))
df_2 = df_2.select("id")
df_1.show()
df_2.show()
df_3 = df_1.alias("df_1").join(df_2.alias("df_2"), df_1.id == df_2.id, "outer")\
.select(\
[coalesce(df_1.id, df_2.id).alias("id")] +\
[col("df_1." + c) for c in df_1.columns if c != "id"])\
.sort("id")
df_3.show()

Peut-être, vous voulez concaténer plus de deux Dataframes.
J'ai trouvé un problème qui utilisent des pandas Dataframe de conversion.

Supposons que vous avez 3 étincelle Dataframe qui à concaténer.

Le code est le suivant:

list_dfs = []
list_dfs_ = []
df = spark.read.json('path_to_your_jsonfile.json',multiLine = True)
df2 = spark.read.json('path_to_your_jsonfile2.json',multiLine = True)
df3 = spark.read.json('path_to_your_jsonfile3.json',multiLine = True)
list_dfs.extend([df,df2,df3])
for df in list_dfs : 
df = df.select([column for column in df.columns]).toPandas()
list_dfs_.append(df)
list_dfs.clear()
df_ = sqlContext.createDataFrame(pd.concat(list_dfs_))

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