Returns a new DataFrame omitting rows with null values

# Returns a new DataFrame omitting rows with null values

df4.na.drop().show()
# +---+------+-----+
# |age|height| name|
# +---+------+-----+
# | 10|    80|Alice|
# +---+------+-----+

Here is what the above code is Doing:
1. The first line calls the na function on the DataFrame df4.
2. The second line calls the drop function on the DataFrame returned by the first line.
3. The third line calls the show function on the DataFrame returned by the second line.