I'm working on this spark java application and I wanted to access structtype object in a structtype object. For instance-
When we take schema of spark dataframe it looks something like this-
root
|-- name: struct (nullable = true)
| |-- firstname: string (nullable = true)
| |-- middlename: string (nullable = true)
| |-- lastname: string (nullable = true)
|-- language: string (nullable = true)
|-- fee: integer (nullable = true)
I wanted to grab the name as a structtype so that I can analyze it further. It would make a sort of chain. But the problem is that at the root level or any level, we can only extract structfield out of structtype and not other structtype.
StructType st = df.schema(); --> we get root level structtype
st.fields(); --> give us array of structfields but if I take name as a structfield i will lose all the fields inside it as 'name' is a StructType and I want to have it as it is.
StructType name = out of st --> this is what I want to achieve.
CodePudding user response:
You can use the parameters and methods mentioned in the official documentation:
schema = StructType([StructField('name', StructType([StructField('firstname', StringType()), StructField('middlename', StringType()), StructField('lastname', StringType())])), StructField('language', StringType()), StructField('fee', IntegerType())])
for f in schema.fields:
if (f.name == "name"):
print(f.dataType)
for f2 in f.dataType.fields:
print(f2.name)
[Out]:
StructType([StructField('firstname', StringType(), True), StructField('middlename', StringType(), True), StructField('lastname', StringType(), True)])
firstname
middlename
lastname