Method drop_columns

datafusion/core/src/dataframe/mod.rs:468–504

Returns a new DataFrame containing all columns except the specified columns. ``` # use datafusion::prelude::*; # use datafusion::error::Result; # use datafusion_common::assert_batches_sorted_eq; # #[tokio::main] # async fn main() -> Result<()> { let ctx = SessionContext::new(); let df = ctx .read_csv("tests/data/example.csv", CsvReadOptions::new()) .await?; // +----+----+----+ // | a | b | c |

(self, columns: &[T])

    /// # }
    /// ```
    pub fn drop_columns<T>(self, columns: &[T]) -> Result<DataFrame>
    where
        T: Into<Column> + Clone,
    {
        let fields_to_drop = columns
            .iter()
            .flat_map(|col| {
                let column: Column = col.clone().into();
                match column.relation.as_ref() {
                    Some(_) => {
                        // qualified_field_from_column returns Result<(Option<&TableReference>, &FieldRef)>
                        vec![self.plan.schema().qualified_field_from_column(&column)]
                    }
                    None => {
                        // qualified_fields_with_unqualified_name returns Vec<(Option<&TableReference>, &FieldRef)>
                        self.plan
                            .schema()
                            .qualified_fields_with_unqualified_name(&column.name)
                            .into_iter()
                            .map(Ok)
                            .collect::<Vec<_>>()
                    }
                }
            })
            .collect::<Result<Vec<_>, _>>()?;
        let expr: Vec<Expr> = self
            .plan
            .schema()
            .fields()
            .into_iter()
            .enumerate()
            .map(|(idx, _)| self.plan.schema().qualified_field(idx))
            .filter(|(qualifier, f)| !fields_to_drop.contains(&(*qualifier, f)))
            .map(|(qualifier, field)| Expr::Column(Column::from((qualifier, field))))
            .collect();
        self.select(expr)
    }

    /// Expand multiple list/struct columns into a set of rows and new columns.
    ///