Method lookup_key

arrow-array/src/array/dictionary_array.rs:365–371

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`].

(&self, value: &str)

    ///
    /// 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();

        (0..rd_buf.len())
            .position(|i| rd_buf.value(i) == value)
            .and_then(K::Native::from_usize)
    }

    /// Returns a reference to the dictionary values array
    pub fn values(&self) -> &ArrayRef {