在spark dataframe列中提取特定字符串后的数字-scala

56lgkhnf 于 2021-05-27 发布在 Spark

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我有一个Dataframe df 带以下格式

|constraint                                     |constraint_status |constraint_msg                                                                                             
 +----------------------------------------------------------------------------------------------------------------+--------------------------------+
 |CompletenessConstraint                        |Success          |Value: 1.0 Notnull condition should be satisfied     
 |UniquenessConstraint                          |Success          |Value: 1.0 Uniqueness condition should be satisfied                            |
 |PatternMatchConstraint                        |Failure          |Expected type of column CHD_ACCOUNT_NUMBER to be StringType                          |
 |MinimumConstraint                             |Success          |Value: 5.1210650000005 Minimum value should be greater than 10.000000 
 |HistogramConstraint                           |Failure          |Can't execute the assertion: key not found: 1242.0!Percentage should be greater than 10.000000|

我想得到后面的数值 Value: 字符串并创建新列 Value .
预期产量

|constraint                                     |constraint_status |constraint_msg                                                       |Value                                        
 +----------------------------------------------------------------------------------------------------------------+--------------------------------+
 |CompletenessConstraint                        |Success          |Value: 1.0 Notnull condition should be satisfied                          |     1.0
 |UniquenessConstraint                          |Success          |Value: 1.0 Uniqueness condition should be satisfied                       |     1.0 
 |PatternMatchConstraint                        |Failure          |Expected type of column CHD_ACCOUNT_NUMBER to be StringType               |     null
 |MinimumConstraint                             |Success          |Value: 5.1210650000005 Minimum value should be greater than 10.000000     |     5.1210650000005 
 |HistogramConstraint                           |Failure          |Can't execute the assertion: key not found: 1242.0!Percentage should be greater than 10.000000| null

我试过以下代码：

df = df.withColumn("Value",split(df("constraint_msg"), "Value\\: (\\d+)").getItem(0))

但是有个错误。需要帮助！
org.apache.spark.sql.analysisexception:无法解析“split”( constraint_msg ，'value\：（\d+）'由于数据类型不匹配：参数1需要字符串类型，但是，' constraint_msg '是数组类型。；；

scala apache-spark apache-spark-sql regex

来源：https://stackoverflow.com/questions/62963217/extracting-number-after-specific-string-in-spark-dataframe-column-scala

2条答案

按热度按时间

1zmg4dgp1#

when..otherwise 将帮助您首先筛选那些不包含 Value: . 假设约束总是以 Value: ，我选择分割后的第二个元素作为所需值。

val df = sc.parallelize(Seq(("CompletenessConstraint", "Success", "Value: 1.0 Notnull condition should be satisfied"), ("PatternMatchConstraint", "Failure", "Expected type of column CHD_ACCOUNT_NUMBER to be StringType"))).toDF("constraint", "constraint_status", "constraint_msg")

val df1 = df.withColumn("Value",when(col("constraint_msg").contains("Value:"),split(df("constraint_msg"), " ").getItem(1)).otherwise(null))

df1.show()
+--------------------+-----------------+--------------------+-----+
|          constraint|constraint_status|      constraint_msg|Value|
+--------------------+-----------------+--------------------+-----+
|CompletenessConst...|          Success|Value: 1.0 Notnul...|  1.0|
|PatternMatchConst...|          Failure|Expected type of ...| null|
+--------------------+-----------------+--------------------+-----+

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k4ymrczo2#

检查以下代码。

scala> df.show(false)
+----------------------+------------------+----------------------------------------------------------------------------------------------+
|constraint            |constraint_status |constraint_msg                                                                                |
+----------------------+------------------+----------------------------------------------------------------------------------------------+
|CompletenessConstraint|Success           |Value: 1.0 Notnull condition should be satisfied                                              |
|UniquenessConstraint  |Success           |Value: 1.0 Uniqueness condition should be satisfied                                           |
|PatternMatchConstraint|Failure           |Expected type of column CHD_ACCOUNT_NUMBER to be StringType                                   |
|MinimumConstraint     |Success           |Value: 5.1210650000005 Minimum value should be greater than 10.000000                         |
|HistogramConstraint   |Failure           |Can't execute the assertion: key not found: 1242.0!Percentage should be greater than 10.000000|
+----------------------+------------------+----------------------------------------------------------------------------------------------+

scala> df
.withColumn("Value",regexp_extract($"constraint_msg","Value: (\\d.\\d+)",1))
.show(false)
+----------------------+------------------+----------------------------------------------------------------------------------------------+---------------+
|constraint            |constraint_status |constraint_msg                                                                                |Value          |
+----------------------+------------------+----------------------------------------------------------------------------------------------+---------------+
|CompletenessConstraint|Success           |Value: 1.0 Notnull condition should be satisfied                                              |1.0            |
|UniquenessConstraint  |Success           |Value: 1.0 Uniqueness condition should be satisfied                                           |1.0            |
|PatternMatchConstraint|Failure           |Expected type of column CHD_ACCOUNT_NUMBER to be StringType                                   |               |
|MinimumConstraint     |Success           |Value: 5.1210650000005 Minimum value should be greater than 10.000000                         |5.1210650000005|
|HistogramConstraint   |Failure           |Can't execute the assertion: key not found: 1242.0!Percentage should be greater than 10.000000|               |
+----------------------+------------------+----------------------------------------------------------------------------------------------+---------------+

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在spark dataframe列中提取特定字符串后的数字-scala

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