alamb commented on a change in pull request #367:
URL: https://github.com/apache/arrow-rs/pull/367#discussion_r641924208
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File path: arrow/src/array/builder.rs
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@@ -383,6 +383,57 @@ impl From<BooleanBufferBuilder> for Buffer {
}
/// Trait for dealing with different array builders at runtime
+///
+/// # Example
+///
+/// ```
+/// # use arrow::{
+/// # array::{ArrayBuilder, ArrayRef, Float64Builder, Int64Builder,
StringArray, StringBuilder},
+/// # error::ArrowError,
+/// # };
+/// # fn main() -> std::result::Result<(), ArrowError> {
+/// // Create
+/// let mut data_builders: Vec<Box<dyn ArrayBuilder>> = vec![
+/// Box::new(Float64Builder::new(1024)),
+/// Box::new(Int64Builder::new(1024)),
+/// Box::new(StringBuilder::new(1024)),
+/// ];
+///
+/// // Fill
+/// data_builders[0]
+/// .as_any_mut()
+/// .downcast_mut::<Float64Builder>()
+/// .unwrap()
+/// .append_value(3.14)?;
+/// data_builders[1]
+/// .as_any_mut()
+/// .downcast_mut::<Int64Builder>()
+/// .unwrap()
+/// .append_value(-1)?;
+/// data_builders[2]
+/// .as_any_mut()
+/// .downcast_mut::<StringBuilder>()
+/// .unwrap()
+/// .append_value("🍎")?;
+///
+/// // Finish
+/// let array_refs: Vec<ArrayRef> = data_builders
+/// .iter_mut()
+/// .map(|builder| builder.finish())
+/// .collect();
+/// assert_eq!(array_refs[0].len(), 1);
+/// assert_eq!(array_refs[1].is_null(0), false);
+/// assert_eq!(
+/// array_refs[2]
+/// .as_any()
+/// .downcast_ref::<StringArray>()
+/// .unwrap()
+/// .value(0),
+/// "🍎"
Review comment:
👌
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