[arrow-rs] branch master updated: minor: clarify docstring on `DictionaryArray::lookup_key` (#1910)

[alamb]

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The following commit(s) were added to refs/heads/master by this push:
     new aee26284f minor: clarify docstring on `DictionaryArray::lookup_key` 
(#1910)
aee26284f is described below

commit aee26284f07ff9af1f2730427a8eb4959bfdec55
Author: Andrew Lamb <and...@nerdnetworks.org>
AuthorDate: Tue Jun 21 07:23:17 2022 -0400

    minor: clarify docstring on `DictionaryArray::lookup_key` (#1910)
    
    * minor: clarify docstring on `DictionaryArray::lookup_key`
    
    * Update arrow/src/array/array_dictionary.rs
    
    Co-authored-by: Liang-Chi Hsieh <vii...@gmail.com>
    
    Co-authored-by: Liang-Chi Hsieh <vii...@gmail.com>
---
 arrow/src/array/array_dictionary.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arrow/src/array/array_dictionary.rs 
b/arrow/src/array/array_dictionary.rs
index b9da60ccf..cff3daabb 100644
--- a/arrow/src/array/array_dictionary.rs
+++ b/arrow/src/array/array_dictionary.rs
@@ -128,7 +128,11 @@ impl<'a, K: ArrowPrimitiveType> DictionaryArray<K> {
         &self.keys
     }
 
-    /// Returns the lookup key by doing reverse dictionary lookup
+    /// If `value` is present in `values` (aka the dictionary),
+    /// returns the corresponding key (index into the `values`
+    /// array). Otherwise returns `None`.
+    ///
+    /// Panics if `values` is not a [`StringArray`].
     pub fn lookup_key(&self, value: &str) -> Option<K::Native> {
         let rd_buf: &StringArray =
             self.values.as_any().downcast_ref::<StringArray>().unwrap();