fix arrow2 python error

Author: wangxiaoying

connectorx-python/src/arrow2.rs

@@ -38,20 +38,16 @@ fn to_ptrs(
     let mut result = vec![];
     let names = schema.fields.iter().map(|f| f.name.clone()).collect();
 
-    for rb in rbs {
+    for rb in rbs.into_iter() {
         let mut cols = vec![];
 
-        for array in rb.columns() {
-            let array_ptr = Box::new(ffi::ArrowArray::empty());
-            let schema_ptr = Box::new(ffi::ArrowSchema::empty());
-            let array_ptr = Box::into_raw(array_ptr);
-            let schema_ptr = Box::into_raw(schema_ptr);
-            unsafe {
-                ffi::export_field_to_c(
-                    &Field::new("", array.data_type().clone(), true),
-                );
-                ffi::export_array_to_c(array.clone());
-            };
+        for array in rb.into_arrays() {
+            let schema_ptr =
+                ffi::export_field_to_c(&Field::new("", array.data_type().clone(), true));
+            let array_ptr = ffi::export_array_to_c(array);
+            let array_ptr = Box::into_raw(Box::new(array_ptr));
+            let schema_ptr = Box::into_raw(Box::new(schema_ptr));
+
             cols.push((array_ptr as uintptr_t, schema_ptr as uintptr_t));
         }
 

connectorx/src/destinations/arrow2/funcs.rs

@@ -5,7 +5,6 @@ use crate::typesystem::{ParameterizedFunc, ParameterizedOn};
 use anyhow::anyhow;
 use arrow2::array::{Array, MutableArray};
 use arrow2::datatypes::Field;
-use std::sync::Arc;
 
 pub struct FNewBuilder;
 

connectorx/src/destinations/arrow2/mod.rs

@@ -18,7 +18,7 @@ pub use errors::{Arrow2DestinationError, Result};
 use fehler::throw;
 use fehler::throws;
 use funcs::{FFinishBuilder, FNewBuilder, FNewField};
-use polars::prelude::{ArrowField, DataFrame, PolarsError, Series};
+use polars::prelude::{DataFrame, PolarsError, Series};
 use std::convert::TryFrom;
 use std::sync::{Arc, Mutex};
 pub use typesystem::Arrow2TypeSystem;
@@ -137,7 +137,7 @@ impl Arrow2Destination {
                     .into_iter()
                     .zip(chunks.1)
                     .map(|(arr, field)| {
-                        let a = Series::try_from((field.name.as_str(), arr)).map_err(|er| {
+                        let a = Series::try_from((field.name.as_str(), arr)).map_err(|_| {
                             PolarsError::ComputeError("Couldn't build Series from box".into())
                         });
                         a