apache spark - why doesn't lit() function work in selectExpr()?

Question

df.selectExpr(func.lit(20)).show()
df.selectExpr("func.lit(20)").show()

Throwing Error :

raise TypeError("Column is not iterable")
TypeError: Column is not iterable

Answer 1

You should either use

df.select(func.lit(20))

or

df.selectExpr("20")

selectExpr expects a raw SQL string that can be selected, while select expects a column object, such as func.lit(20), or a column name as a string.

columns should not be used in selectExpr.