Dandandan commented on code in PR #3614:
URL: https://github.com/apache/arrow-datafusion/pull/3614#discussion_r980254141
##########
datafusion/physical-expr/src/regex_expressions.rs:
##########
@@ -178,10 +197,125 @@ pub fn regexp_replace<T: OffsetSizeTrait>(args:
&[ArrayRef]) -> Result<ArrayRef>
}
}
+fn _regexp_replace_early_abort<T: OffsetSizeTrait>(
+ input_array: &GenericStringArray<T>,
+) -> Result<ArrayRef> {
+ // Mimicing the existing behavior of regexp_replace, if any of the scalar
arguments
+ // are actuall null, then the result will be an array of the same size but
with nulls.
+ Ok(new_null_array(input_array.data_type(), input_array.len()))
+}
+
+fn _regexp_replace_static_pattern<T: OffsetSizeTrait>(
+ args: &[ArrayRef],
+) -> Result<ArrayRef> {
+ // Special cased regex_replace implementation for the scenerio where
+ // both the pattern itself and the flags are scalars. This means we can
+ // skip regex caching system and basically hold a single Regex object
+ // for the replace operation.
+
+ let string_array = downcast_string_array_arg!(args[0], "string", T);
+ let pattern = fetch_string_arg!(args[1], "pattern", T,
_regexp_replace_early_abort);
+ let replacement_array = downcast_string_array_arg!(args[2], "replacement",
T);
+ let flags = match args.len() {
+ 3 => None,
+ 4 => Some(fetch_string_arg!(args[3], "flags", T,
_regexp_replace_early_abort)),
+ other => {
+ return Err(DataFusionError::Internal(format!(
+ "regexp_replace was called with {} arguments. It requires at
least 3 and at most 4.",
+ other
+ )))
+ }
+ };
+
+ // Embed the flag (if it exists) into the pattern
+ let (pattern, replace_all) = match flags {
+ Some("g") => (pattern.to_string(), true),
+ Some(flags) => (
+ format!("(?{}){}", flags.to_string().replace('g', ""), pattern),
+ flags.contains('g'),
+ ),
+ None => (pattern.to_string(), false),
+ };
+
+ let re = Regex::new(&pattern)
+ .map_err(|err| DataFusionError::Execution(err.to_string()))?;
+
+ let result = string_array
+ .iter()
+ .zip(replacement_array.iter())
Review Comment:
I guess the case with both a scalar replacement + scalar pattern (as in the
example query) might be the most common - so maybe best to implement this case
in this PR?
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