iterate over pyspark dataframe columns

you can try this one :

nullDf= df.select([count(when(col(c).isNull(), c)).alias(c) for c in df.columns]) 
nullDf.show() 

it will give you a list of columns with the number of null its null values.

Have you tried something like this:

names = df.schema.names
for name in names:
    print(name + ': ' + df.where(df[name].isNull()).count())

You can see how this could be modified to put the information into a dictionary or some other more useful format.