I have a Spark DataFrame (using PySpark 1.5.1) and would like to add a new column.

I've tried the following without any success:

```
type(randomed_hours) # => list

# Create in Python and transform to RDD

new_col = pd.DataFrame(randomed_hours, columns=['new_col'])

spark_new_col = sqlContext.createDataFrame(new_col)

my_df_spark.withColumn("hours", spark_new_col["new_col"])

```

Also got an error using this:

```
my_df_spark.withColumn("hours",  sc.parallelize(randomed_hours))

```

So how do I add a new column (based on Python vector) to an existing DataFrame with PySpark?