jorgecarleitao commented on a change in pull request #9243:
URL: https://github.com/apache/arrow/pull/9243#discussion_r562390994
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File path: rust/datafusion/src/physical_plan/string_expressions.rs
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@@ -34,42 +35,553 @@ macro_rules! downcast_vec {
}};
}
-/// concatenate string columns together.
-pub fn concatenate(args: &[ArrayRef]) -> Result<StringArray> {
+/// Returns the numeric code of the first character of the argument.
+pub fn ascii<T: StringOffsetSizeTrait>(args: &[ArrayRef]) ->
Result<Int32Array> {
+ let array = args[0]
+ .as_any()
+ .downcast_ref::<GenericStringArray<T>>()
+ .unwrap();
+ // first map is the iterator, second is for the `Option<_>`
+ Ok(array
+ .iter()
+ .map(|x| {
+ x.map(|x: &str| {
+ let mut chars = x.chars();
+ chars.next().map_or(0, |v| v as i32)
+ })
+ })
+ .collect())
+}
+
+/// Removes the longest string containing only characters in characters (a
space by default) from the start and end of string.
+pub fn btrim<T: StringOffsetSizeTrait>(args: &[ArrayRef]) ->
Result<StringArray> {
+ match args.len() {
+ 0 => Err(DataFusionError::Internal(
+ "btrim was called with 0 arguments. It requires at least
1.".to_string(),
+ )),
+ 1 => {
+ let string_array = args[0]
+ .as_any()
+ .downcast_ref::<GenericStringArray<T>>()
+ .unwrap();
+
+ Ok(string_array
+ .iter()
+ .map(|x| x.map(|x: &str| x.trim()))
+ .collect())
+ }
+ 2 => {
+ let string_array = args[0]
+ .as_any()
+ .downcast_ref::<GenericStringArray<T>>()
+ .unwrap();
+
+ let characters_array = args[1]
+ .as_any()
+ .downcast_ref::<GenericStringArray<T>>()
+ .unwrap();
+
+ Ok(string_array
+ .iter()
+ .enumerate()
+ .map(|(i, x)| {
+ if characters_array.is_null(i) {
+ None
+ } else {
+ x.map(|x: &str| {
+ let chars: Vec<char> =
+ characters_array.value(i).chars().collect();
+ x.trim_start_matches(&chars[..])
+ .trim_end_matches(&chars[..])
+ })
+ }
+ })
+ .collect())
+ }
+ other => Err(DataFusionError::Internal(format!(
+ "btrim was called with {} arguments. It requires at most 2.",
+ other
+ ))),
+ }
+}
+
+/// Returns number of characters in the string.
+pub fn character_length_i32(args: &[ArrayRef]) -> Result<Int32Array> {
+ let array = args[0]
+ .as_any()
+ .downcast_ref::<GenericStringArray<i32>>()
+ .unwrap();
+ // first map is the iterator, second is for the `Option<_>`
+ Ok(array
+ .iter()
+ .map(|x| x.map(|x: &str| x.graphemes(true).count() as i32))
+ .collect())
+}
+
+/// Returns number of characters in the string.
+pub fn character_length_i64(args: &[ArrayRef]) -> Result<Int64Array> {
+ let array = args[0]
+ .as_any()
+ .downcast_ref::<GenericStringArray<i64>>()
+ .unwrap();
+ // first map is the iterator, second is for the `Option<_>`
+ Ok(array
+ .iter()
+ .map(|x| x.map(|x: &str| x.graphemes(true).count() as i64))
+ .collect())
+}
+
+/// Returns the character with the given code.
+pub fn chr(args: &[ArrayRef]) -> Result<StringArray> {
+ let array = args[0].as_any().downcast_ref::<Int64Array>().unwrap();
+ // first map is the iterator, second is for the `Option<_>`
+ Ok(array
Review comment:
*and remove this `Ok` from here, so that `collect` is implicitly treated
as `collect<Result<_>>` instead of `collect<_>`
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