Creating a UDF for vector data
A dataframe df is available, having a column output of type vector. Its first five rows are shown in the console.
Este exercício faz parte do curso
Introduction to Spark SQL in Python
Instruções do exercício
- Create a UDF called
first_udf. It selects the first element of a vector column. Set the result to a default value of 0.0 for any item that is not a vector containing at least one item and cast the output as a float. - Use the
selectoperation ondfto applyfirst_udfto theoutputcolumn.
Exercício interativo prático
Experimente este exercício completando este código de exemplo.
# Selects the first element of a vector column
first_udf = ____(lambda x:
____(x.indices[0])
if (x and hasattr(x, "toArray") and x.____())
else 0.0,
FloatType())
# Apply first_udf to the output column
df.select(____("output").alias("result")).show(5)