How do I detect if a Spark DataFrame has a column

Just assume it exists and let it fail with Try. Plain and simple and supports an arbitrary nesting:

import scala.util.Try
import org.apache.spark.sql.DataFrame

def hasColumn(df: DataFrame, path: String) = Try(df(path)).isSuccess

val df = sqlContext.read.json(sc.parallelize(
  """{"foo": [{"bar": {"foobar": 3}}]}""" :: Nil))

hasColumn(df, "foobar")
// Boolean = false

hasColumn(df, "foo")
// Boolean = true

hasColumn(df, "foo.bar")
// Boolean = true

hasColumn(df, "foo.bar.foobar")
// Boolean = true

hasColumn(df, "foo.bar.foobaz")
// Boolean = false

Or even simpler:

val columns = Seq(
  "foobar", "foo", "foo.bar", "foo.bar.foobar", "foo.bar.foobaz")

columns.flatMap(c => Try(df(c)).toOption)
// Seq[org.apache.spark.sql.Column] = List(
//   foo, foo.bar AS bar#12, foo.bar.foobar AS foobar#13)

Python equivalent:

from pyspark.sql.utils import AnalysisException
from pyspark.sql import Row


def has_column(df, col):
    try:
        df[col]
        return True
    except AnalysisException:
        return False

df = sc.parallelize([Row(foo=[Row(bar=Row(foobar=3))])]).toDF()

has_column(df, "foobar")
## False

has_column(df, "foo")
## True

has_column(df, "foo.bar")
## True

has_column(df, "foo.bar.foobar")
## True

has_column(df, "foo.bar.foobaz")
## False