pyflink.table.expression.Expression.is_json

Expression.is_json(json_type: JsonType | None = None) → Expression[bool]

Determine whether a given string is valid JSON.

Specifying the optional json_type argument puts a constraint on which type of JSON object is allowed. If the string is valid JSON, but not that type, false is returned. The default is JsonType.VALUE.

Examples:

>>> lit('1').is_json() # True
>>> lit('[]').is_json() # True
>>> lit('{}').is_json() # True

>>> lit('"abc"').is_json() # True
>>> lit('abc').is_json() # False
>>> null_of(DataTypes.STRING()).is_json() # False

>>> lit('1').is_json(JsonType.SCALAR) # True
>>> lit('1').is_json(JsonType.ARRAY) # False
>>> lit('1').is_json(JsonType.OBJECT) # False

>>> lit('{}').is_json(JsonType.SCALAR) # False
>>> lit('{}').is_json(JsonType.ARRAY) # False
>>> lit('{}').is_json(JsonType.OBJECT) # True

Added in version 1.12.0.