Answers for "how to drop all the column with n/a in pandas"

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|
# +---+------+-----+

dropna threshold

#dropping columns having more than 50% missing values(1994/2==1000)
df=df.dropna(thresh=1000,axis=1)