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使用pyspark進行包含和精確模式匹配

2021-10-24 10:25:50 前端設計

我有一個如下所示的資料集:

campaign_name
abcloancde
abcsolcdf
abcemicdef
emic_estore
Personalloa-nemic_sol
personalloa_nemic
abc/emic-dg-upi:bol

campaign_name列名在哪里我還有一個dictionary像下面這樣:

使用 pyspark 進行包含和精確模式匹配

根據我的用例,我必須根據長度terms降序對字典進行排序,并且必須將其與campaign_name進行映射無論terms首次發現campaign_name,其相關的product_categoryproduct應該接走。為此,我撰寫了以下代碼并且它作業正常:

#Dataset loaded below
initialData = spark.read.option("header", "true").csv("file://..../sample_data.csv")
initialData.show()
#Dictionary loaded below
df = spark.read.option("header", 
"true").csv("file://..../mapper.csv")

df_contains = df.filter(df.function == 'contains').drop("function")
df_contains = df_contains.orderBy(length(col("terms")).desc())
w = Window.partitionBy(lit('A')).orderBy(length(col("terms")).desc())
df_contains = df_contains.withColumn("rw", row_number().over(w))


df3 = df_contains.na.fill("").groupBy(lit(1)).agg(collect_list(
    concat(col("rw"), lit(":"), col("terms"), lit(":"), col("product_category"), lit(":"), col("product"))).alias(
    "Check")).withColumn("Check", concat_ws(",", col("Check"))).drop("1")


def categoryFunction(name, Check):
    # checkList = Check.lower().split(",")
    out = ""
    match = False
    for Key in Check.lower().split(","):
        keyword = Key.split(":", 2)
        terms = keyword[1]
        tempOut = keyword[2]
        if terms in name.lower():
            out = tempOut
            match = True
        if match:
            break
    return out


def categoryFunction1(name, Check):
    # checkList = Check.lower().split(",")
    out = ""
    match = False
    for Key in Check.lower().split(","):
        keyword = Key.split(":", 2)
        terms = keyword[1]
        tempOut = keyword[2]
        if terms == name.lower():
            out = tempOut
            match = True
        if match:
            break
    return out


categoryUDF = udf(categoryFunction, StringType())
categoryUDF1 = udf(categoryFunction1, StringType())

df4 = initialData.crossJoin(df3)

finalDF = df4.withColumn("out", categoryUDF(col("campaign_name"), col("Check"))).drop("Check").withColumn("out", split(
    col("out"), ":")).withColumn("product_category", col("out")[0]).withColumn("product", col("out")[1]).drop(
    "out").withColumn("prod", when(col("product").isNull(), "other").otherwise(col("product"))).withColumn("prod_cat",
                                                                                                           when(
                                                                                                               col("product_category") == "",
                                                                                                               "other").otherwise(
                                                                                                               col("product_category"))).drop(
    "product", "product_category")

它給了我以下正確的輸出:

 --------------------- ----- -------- 
|campaign_name        |prod |prod_cat|
 --------------------- ----- -------- 
|abcloancde           |     |lending |
|abcsolcdf            |sol  |lending |
|abcemicdef           |other|other   |
|emic_estore          |other|other   |
|personalloan-emic_sol|     |lending |
|personalloan_emic    |     |lending |
|abc/emic-dg-upi:bol  |other|other   |
 --------------------- ----- -------- 

現在,我只想選擇campaign_nameswhereprodprod_catvalues are other獲得這樣以后campaign_names我有分裂campaign_names的基礎上"_",再次對運行狀況dictionary,其中function="match"并挑選productproduct_category為完成contains

I have written a categoryFunction1 UDF for this and it actually works when I am filtering out the required dataset for the match condition and doing whatever I need to do and then doing union with the above output(which updates the values for "other").

Is there any way like by using "case...when..then" which explodes the data as I need and doing the crossJoin and then picking up the FIRST EXACT MATCH value? Because I am dealing with billions of records so wanted to think of a more optimal solution.

Final expected output(contains exact):

 --------------------- ----- -------- 
|campaign_name        |prod |prod_cat|
 --------------------- ----- -------- 
|abcloancde           |     |lending |
|abcsolcdf            |sol  |lending |
|abcemicdef           |other|other   |
|emic_estore          |emic |cards   |
|personalloan-emic_sol|     |lending |
|personalloan_emic    |     |lending |
|abc/emic-dg-upi:bol  |other|other   |
 --------------------- ----- -------- 

Catch
我在問題中遺漏了一種情況。在比較包含和精確匹配時,我必須消除所有分隔符,我可以考慮所有分隔符,但只需要在基礎上拆分單詞"_"然后比較它們。

任何建議都非常感謝。

uj5u.com熱心網友回復:

與使用可以利用 spark 優化的 spark api 相比,spark 集群上的 UDF 可能很昂貴。我理解您創建df3包含在您的 udfs 中的原因,但這可能不是必需的。特別是當您的字典資料的大小可能會增長并且要創建的聚合df3可能很昂貴并導致資料溢位(從記憶體到磁盤)時,因為您將所有內容分組為 1 行。如果它比活動資料小得多,您可以選擇broadcast帶有字典資料的資料框。

根據您的樣本資料df_contains具有以下內容

df_contains = dictionaryDf.filter(dictionaryDf.function == 'contains').drop("function").na.fill("")
df_contains.show(truncate=False)
 ----- ---------------- ------- 
|terms|product_category|product|
 ----- ---------------- ------- 
|loan |Lending         |       |
|sol  |Lending         |SOL    |
 ----- ---------------- ------- 

僅使用 spark api 的另一種方法是:

方法一

第1部分

注意。您已經使用 UDF 完成了第 1 部分

  1. 左加入字典資料(廣播,如果這可以提高您的性能)關于該術語是否位于廣告系列名稱中。
  2. 然后,您可以首先使用視窗函式行號來識別最長的項,或者按照您的描述:

我必須根據術語的長度降序對字典進行排序,并且必須將其與 Campaign_name 列進行映射

  1. 選擇您想要的列并使用您的案例運算式邏輯(即與何時)

該方法可以編碼如下:

from pyspark.sql import functions as F

output_df = (
    # Step 1
    initial_data.join(
                    F.broadcast(df_contains),
                    F.col("campaign_name").contains(F.col("terms")),
                    "left"
                )
    # Step 2
                .withColumn(
                    "rn",
                    F.row_number().over(
                        Window.partitionBy("campaign_name")
                              .orderBy(
                                  F.length(F.col("terms")).desc()
                              )
                    )
                )
                .filter("rn=1")
    # Step 3
                .select(
                    "campaign_name",
                    F.when(
                        F.col("product").isNull(),"other"
                    ).otherwise(F.col("product")).alias("prod"),
                    F.when(
                        F.col("product_category").isNull(),"other"
                    ).otherwise(F.col("product_category")).alias("prod_cat")
                )
)
output_df.show(truncate=False)

這會導致以下輸出(注意,spark 中的行排序是不確定的,除非指定了順序):

 --------------------- ----- -------- 
|campaign_name        |prod |prod_cat|
 --------------------- ----- -------- 
|abc/emic-dg-upi:bol  |other|other   |
|abcemicdef           |other|other   |
|abcloancde           |     |Lending |
|abcsolcdf            |SOL  |Lending |
|emic_estore          |other|other   |
|personalloan-emic_sol|     |Lending |
|personalloan_emic    |     |Lending |
 --------------------- ----- -------- 

第2部分

我們可能會使用與上述類似的方法解決您的其余問題

  1. Split the campaign_name by _ and use explode to get multiple rows for each piece
  2. Left Join on the split campaign name, aliased below as cname_split, and where prod and prod_cat are equal to other for the split campaign names
  3. Instead of using a when/case expression to check for null matches and re-assign the original value we may use coalesce which assigns the first non-null value
  4. Since we have multiple rows for each campaign_name after the explode, we may aggregate, however in the example below, I've used row_number to filter the duplicate entries and order by available product names.

NB. df_match as referenced below was retrieved using

df_match = dictionaryDf.filter(dictionaryDf.function == 'match').drop("function").na.fill("")
df_match.show(truncate=False)
 ------------ ---------------- ------- 
|terms       |product_category|product|
 ------------ ---------------- ------- 
|personalloan|Lending         |UL     |
|emic        |Cards           |EMIC   |
 ------------ ---------------- ------- 

Code:

from pyspark.sql import functions as F

output_df2 = (
    # Step 1
    output_df.select(
                 "*",
                 F.explode(F.split("campaign_name","_")).alias("cname_split")
             )
    # Step 2
             .join(
                 df_match,
                 (
                     F.col("campaign_name").contains("_") &
                     F.col("cname_split").contains(F.col("terms")) &
                     (F.col("prod") == "other") &
                     (F.col("prod_cat") == "other")
                 ),
                 "left"
             )
    # Step 3
             .select(
                 "campaign_name",
                 F.coalesce("product","prod").alias("prod"),
                 F.coalesce("product_category","prod_cat").alias("prod_cat"),
    # Step 4
                 F.row_number().over(
                     Window.partitionBy("campaign_name")
                           .orderBy(
                               F.col("product").isNull()
                           )
                 ).alias("rn")
             )
             .filter("rn=1")
             .drop("rn")
)

output_df2.show(truncate=False)
 --------------------- ----- -------- 
|campaign_name        |prod |prod_cat|
 --------------------- ----- -------- 
|abc/emic-dg-upi:bol  |other|other   |
|abcemicdef           |other|other   |
|abcloancde           |     |Lending |
|abcsolcdf            |SOL  |Lending |
|emic_estore          |EMIC |Cards   |
|personalloan-emic_sol|     |Lending |
|personalloan_emic    |     |Lending |
 --------------------- ----- -------- 

Approach 2

This is similar to the approach above however, it is more optimal as it achieves it's aim using less joins.

Code:

from pyspark.sql import functions as F

output_df3 = (
    initial_data.withColumn("cname_split",F.explode(F.split("campaign_name","_")))
                .join(
                    dictionaryDf,
                    (
                        (
                            (F.col("function")=="contains") &
                            F.col("campaign_name").contains(F.col("terms")) 
                        ) | 
                        (
                           (F.col("function")=="match") &
                           F.col("campaign_name").contains("_") &
                           F.col("cname_split").contains(F.col("terms")) 
                           
                        )
                    ),
                    "left"
                )
                .withColumn(
                    "empty_is_other",
                    F.when(
                        (
                            F.col("product").isNull() & 
                            F.col("product_category").isNull()
                        ),
                        "other"
                    )
                )
                .withColumn(
                    "rn",
                    F.row_number().over(
                        Window.partitionBy("campaign_name")
                              .orderBy(
                                  F.when(
                                      F.col("function").isNull(),3
                                  ).when(
                                      F.col("function")=="match",2
                                  ).otherwise(1),
                                  F.length(F.col("terms")).desc(),
                                  F.col("product").isNull()
                              )
                    )
                )
                .filter("rn=1")
                .select(
                    "campaign_name",
                    F.coalesce("product","empty_is_other").alias("prod"),
                    F.coalesce("product_category","empty_is_other").alias("prod_cat"),
                )
                .na.fill("")
)
output_df3.show(truncate=False)

Outputs

 --------------------- ----- -------- 
|campaign_name        |prod |prod_cat|
 --------------------- ----- -------- 
|abc/emic-dg-upi:bol  |other|other   |
|abcemicdef           |other|other   |
|abcloancde           |     |Lending |
|abcsolcdf            |SOL  |Lending |
|emic_estore          |EMIC |Cards   |
|personalloan-emic_sol|     |Lending |
|personalloan_emic    |     |Lending |
 --------------------- ----- -------- 

Output before .filter("rn=1") for clarification

 --------------------- ------------------- ------------ ---------------- ------- -------- -------------- --- 
|campaign_name        |cname_split        |terms       |product_category|product|function|empty_is_other|rn |
 --------------------- ------------------- ------------ ---------------- ------- -------- -------------- --- 
|abc/emic-dg-upi:bol  |abc/emic-dg-upi:bol|null        |null            |null   |null    |other         |1  |
|abcemicdef           |abcemicdef         |null        |null            |null   |null    |other         |1  |
|abcloancde           |abcloancde         |loan        |Lending         |null   |contains|null          |1  |
|abcsolcdf            |abcsolcdf          |sol         |Lending         |SOL    |contains|null          |1  |
|emic_estore          |emic               |emic        |Cards           |EMIC   |match   |null          |1  |
|emic_estore          |estore             |null        |null            |null   |null    |other         |2  |
|personalloan-emic_sol|personalloan-emic  |loan        |Lending         |null   |contains|null          |1  |
|personalloan-emic_sol|sol                |loan        |Lending         |null   |contains|null          |2  |
|personalloan-emic_sol|personalloan-emic  |sol         |Lending         |SOL    |contains|null          |3  |
|personalloan-emic_sol|sol                |sol         |Lending         |SOL    |contains|null          |4  |
|personalloan-emic_sol|personalloan-emic  |personalloan|Lending         |UL     |match   |null          |5  |
|personalloan-emic_sol|personalloan-emic  |emic        |Cards           |EMIC   |match   |null          |6  |
|personalloan_emic    |personalloan       |loan        |Lending         |null   |contains|null          |1  |
|personalloan_emic    |emic               |loan        |Lending         |null   |contains|null          |2  |
|personalloan_emic    |personalloan       |personalloan|Lending         |UL     |match   |null          |3  |
|personalloan_emic    |emic               |emic        |Cards           |EMIC   |match   |null          |4  |
 --------------------- ------------------- ------------ ---------------- ------- -------- -------------- --- 

Update 1

In response to question update:

Catch:

There is one scenario that I missed in the question. I have to eliminate all the delimiters while comparing for contains and for the exact match I can consider all the delimiters but just have to split the words on the basis of "_" and then compare them.

regexp_replace was used to remove special characters. See update below:

output_df3 = ( # _/:
    initial_data.withColumn("cname_split",F.explode(F.split("campaign_name","_")))
                .withColumn(
                    "campaign_name_clean",
                    F.regexp_replace(
                        F.lower(F.col("campaign_name")),
                        '[^a-zA-Z0-9]',
                        ""
                    )
                )
                .join(
                    dictionaryDf,
                    (
                        (
                            (F.col("function")=="contains") &
                            F.col("campaign_name_clean").contains(F.col("terms")) 
                        ) | 
                        (
                           (F.col("function")=="match") &
                           F.col("campaign_name").contains("_") &
                           (F.col("cname_split")==F.col("terms"))
                           
                        )
                    ),
                    "left"
                )
                .withColumn(
                    "empty_is_other",
                    F.when(
                        (
                            (
                                (F.col("function")=="contains") | F.col("function").isNull()
                            ) &
                            F.col("product").isNull() & 
                            F.col("product_category").isNull()
                        ),
                        "other"
                    )
                )
                .withColumn(
                    "rn",
                    F.row_number().over(
                        Window.partitionBy("campaign_name")
                              .orderBy(
                                  F.when(
                                      F.col("function").isNull(),3
                                  ).when(
                                      F.col("function")=="match",2
                                  ).otherwise(1),
                                  F.length(F.col("terms")).desc(),
                                  F.col("product").isNull()
                              )
                    )
                )
                .filter("rn=1")
                .select(
                    "campaign_name",
                    F.coalesce("product","empty_is_other").alias("prod"),
                    F.coalesce("product_category","empty_is_other").alias("prod_cat"),
                )
                .na.fill("")
)
output_df3.show(truncate=False)

Outputs:

 --------------------- ----- -------- 
|campaign_name        |prod |prod_cat|
 --------------------- ----- -------- 
|Personalloa-nemic_sol|     |Lending |
|abc/emic-dg-upi:bol  |other|other   |
|abcemicdef           |other|other   |
|abcloancde           |     |Lending |
|abcsolcdf            |SOL  |Lending |
|emic_estore          |EMIC |Cards   |
|personalloa_nemic    |     |Lending |
 --------------------- ----- -------- 

Output before .filter("rn=1") for debugging purposes

 --------------------- ------------------- ------------------- ----- ---------------- ------- -------- -------------- --- 
|campaign_name        |cname_split        |campaign_name_clean|terms|product_category|product|function|empty_is_other|rn |
 --------------------- ------------------- ------------------- ----- ---------------- ------- -------- -------------- --- 
|Personalloa-nemic_sol|Personalloa-nemic  |personalloanemicsol|loan |Lending         |null   |contains|null          |1  |
|Personalloa-nemic_sol|sol                |personalloanemicsol|loan |Lending         |null   |contains|null          |2  |
|Personalloa-nemic_sol|Personalloa-nemic  |personalloanemicsol|sol  |Lending         |SOL    |contains|null          |3  |
|Personalloa-nemic_sol|sol                |personalloanemicsol|sol  |Lending         |SOL    |contains|null          |4  |
|abc/emic-dg-upi:bol  |abc/emic-dg-upi:bol|abcemicdgupibol    |null |null            |null   |null    |other         |1  |
|abcemicdef           |abcemicdef         |abcemicdef         |null |null            |null   |null    |other         |1  |
|abcloancde           |abcloancde         |abcloancde         |loan |Lending         |null   |contains|null          |1  |
|abcsolcdf            |abcsolcdf          |abcsolcdf          |sol  |Lending         |SOL    |contains|null          |1  |
|emic_estore          |emic               |emicestore         |emic |Cards           |EMIC   |match   |null          |1  |
|emic_estore          |estore             |emicestore         |null |null            |null   |null    |other         |2  |
|personalloa_nemic    |personalloa        |personalloanemic   |loan |Lending         |null   |contains|null          |1  |
|personalloa_nemic    |nemic              |personalloanemic   |loan |Lending         |null   |contains|null          |2  |
 --------------------- ------------------- ------------------- ----- ---------------- ------- -------- -------------- --- 

Let me know if this works for you.

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