[SPARK-25226] Extend functionality of from_json to support arrays of differently-typed elements

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Won't Fix
• Affects Version/s: 2.3.1
• Component/s: PySpark, Spark Core
• Assignee: Unassigned
• Reporter: Yuriy Davygora
• Created: 24/Aug/18 10:55
• Updated: 12/Dec/22 18:11
• Resolved: 28/Aug/18 07:30

Description

At the moment, the 'from_json' function only supports a STRUCT or an ARRAY of STRUCTS as input. Support for ARRAY of primitives is, apparently, coming with Spark 2.4, but it will only support arrays of elements of same data type. It will not, for example, support JSON-arrays like

["string_value", 0, true, null]

which is JSON-valid with schema

{"containsNull":true,"elementType":["string","integer","boolean"],"type":"array"}

We would like to kindly ask you to add support for different-typed element arrays in the 'from_json' function. This will necessitate extending the functionality of ArrayType or maybe adding a new type (refer to [SPARK-25225])