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Posted to issues@spark.apache.org by "Daniel Davies (Jira)" <ji...@apache.org> on 2022/08/01 18:54:00 UTC
[jira] [Updated] (SPARK-39937) Substring
[ https://issues.apache.org/jira/browse/SPARK-39937?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Daniel Davies updated SPARK-39937:
----------------------------------
Description:
Hello,
We hit a potential limitation of the substring function today that we think might be useful to contribute back to spark, relating to that fact that [substring |https://github.com/apache/spark/blob/775b5ced70c87d6a8709f44eb4a5de48c286a51d/sql/core/src/main/scala/org/apache/spark/sql/functions.scala#L2952] only takes integers for it's pos and len parameters.
Consider the case where you have a list of ID's, and you need to find substrings in these IDs that are dependent on another column (for example, a column expressing the kind of product that the ID represents).
e.g.
{{Table:}}
ID | Type
{+}----------{-}{-}{+}-------+
ABCD12345 | Water
{+}----------{-}{-}{+}-------+
ABCD12 | Soda
{+}----------{-}{-}{+}-------+
Desired:
ID | Type
{+}----------{-}{-}{+}-------+
12345 | Water
{+}----------{-}{-}{+}-------+
12 | Soda
{+}----------{-}{-}{+}-------+
At the moment, you can only extract substrings of fixed position and length- but if IDs have a variable suffix, it may be desirable to run a substring of different lengths based on the 'Type' column.
In this case, it's fairly straightforward to solve with a chain of .when statements; but if there are thousands of types, it may not be as easy.
This seems fairly niche, but I'd be happy to give the implementation a go if this is something that the community would find useful/ has been seen before.
was:
Hello,
We hit a potential limitation of the substring function today that we think might be useful to contribute back to spark, relating to that fact that [substring |https://github.com/apache/spark/blob/775b5ced70c87d6a8709f44eb4a5de48c286a51d/sql/core/src/main/scala/org/apache/spark/sql/functions.scala#L2952] only takes integers for it's pos and len parameters.
Consider the case where you have a list of ID's, and you need to find substrings in these IDs that are dependent on another column (for example, a column expressing the kind of product that the ID represents).
e.g.
{{Table:}}
{{}}
{{}}
ID | Type
+-----------+--------+
ABCD12345 | Water
+-----------+--------+
ABCD12 | Soda
+-----------+--------+
{{}}
Desired:
ID | Type
+-----------+--------+
12345 | Water
+-----------+--------+
12 | Soda
+-----------+--------+
At the moment, you can only extract substrings of fixed position and length- but if IDs have a variable suffix, it may be desirable to run a substring of different lengths based on the 'Type' column.
In this case, it's fairly straightforward to solve with a chain of .when statements; but if there are thousands of types, it may not be as easy.
This seems fairly niche, but I'd be happy to give the implementation a go if this is something that the community would find useful/ has been seen before.
> Substring
> ---------
>
> Key: SPARK-39937
> URL: https://issues.apache.org/jira/browse/SPARK-39937
> Project: Spark
> Issue Type: New Feature
> Components: Spark Core
> Affects Versions: 3.2.2
> Reporter: Daniel Davies
> Priority: Minor
>
> Hello,
> We hit a potential limitation of the substring function today that we think might be useful to contribute back to spark, relating to that fact that [substring |https://github.com/apache/spark/blob/775b5ced70c87d6a8709f44eb4a5de48c286a51d/sql/core/src/main/scala/org/apache/spark/sql/functions.scala#L2952] only takes integers for it's pos and len parameters.
> Consider the case where you have a list of ID's, and you need to find substrings in these IDs that are dependent on another column (for example, a column expressing the kind of product that the ID represents).
> e.g.
> {{Table:}}
> ID | Type
> {+}----------{-}{-}{+}-------+
> ABCD12345 | Water
> {+}----------{-}{-}{+}-------+
> ABCD12 | Soda
> {+}----------{-}{-}{+}-------+
> Desired:
> ID | Type
> {+}----------{-}{-}{+}-------+
> 12345 | Water
> {+}----------{-}{-}{+}-------+
> 12 | Soda
> {+}----------{-}{-}{+}-------+
> At the moment, you can only extract substrings of fixed position and length- but if IDs have a variable suffix, it may be desirable to run a substring of different lengths based on the 'Type' column.
> In this case, it's fairly straightforward to solve with a chain of .when statements; but if there are thousands of types, it may not be as easy.
> This seems fairly niche, but I'd be happy to give the implementation a go if this is something that the community would find useful/ has been seen before.
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