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Jefffrey pushed a commit to branch main
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The following commit(s) were added to refs/heads/main by this push:
new a16c4584d1 support white space prefixed parse for ints and floats
(#10374)
a16c4584d1 is described below
commit a16c4584d1fd194d236c1757e92ebcb0837cb0f0
Author: RIchard Baah <[email protected]>
AuthorDate: Mon Jul 20 08:13:13 2026 -0400
support white space prefixed parse for ints and floats (#10374)
# Which issue does this PR close?
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- Closes half of #9538.
# Rationale for this change
currently parsing ints and floats with white space prefiing the number
caused the cast to fail
```rust
assert_eq!(Float64Type::parse("\n\t\n\t\n40.5123"), Some(40.5123));
assert_eq!(Float64Type::parse(" 1.5"), Some(1.5));
assert_eq!(Int32Type::parse(" 3"), Some(3));
assert_eq!(Int32Type::parse(" 30"), Some(30));
```
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# What changes are included in this PR?
this PR adds a check to the string before parsing. it checks the first
byte, if its not an ascii digit it will trim the left side of the
string.
Performance was a consideration to avoid regressions here — see
https://github.com/apache/arrow-rs/pull/9537#issuecomment-4085626688. In
the worst case where a string doesn't need trimming (no leading
whitespace), the cost is just one slice operation to grab the first byte
plus a range comparison to check if it's an ASCII digit.
benchmarks show no significant change
<img width="1155" height="493" alt="Image 7-18-26 at 1 02 PM"
src="https://github.com/user-attachments/assets/911560a4-bc4f-4dde-83a0-858e4a470bf8";
/>
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# Are these changes tested?
yes. I created a test with 12 assertiosn to validate behavoir
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# Are there any user-facing changes?
yes. arrow-rs/datafusion cast operations will no longer fail when a
number is prefixed with white space.
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---------
Co-authored-by: Richard Baah <[email protected]>
---
arrow-cast/src/parse.rs | 44 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
diff --git a/arrow-cast/src/parse.rs b/arrow-cast/src/parse.rs
index f4033f08b3..57fbdd40ac 100644
--- a/arrow-cast/src/parse.rs
+++ b/arrow-cast/src/parse.rs
@@ -445,6 +445,7 @@ pub trait Parser: ArrowPrimitiveType {
impl Parser for Float16Type {
fn parse(string: &str) -> Option<f16> {
+ let string = truncate_white_space(string);
lexical_core::parse(string.as_bytes())
.ok()
.map(f16::from_f32)
@@ -453,23 +454,44 @@ impl Parser for Float16Type {
impl Parser for Float32Type {
fn parse(string: &str) -> Option<f32> {
+ let string = truncate_white_space(string);
lexical_core::parse(string.as_bytes()).ok()
}
}
impl Parser for Float64Type {
fn parse(string: &str) -> Option<f64> {
+ let string = truncate_white_space(string);
lexical_core::parse(string.as_bytes()).ok()
}
}
+#[inline]
+fn truncate_white_space(string: &str) -> &str {
+ if string
+ .as_bytes()
+ .first()
+ .is_some_and(|first_byte| !first_byte.is_ascii_digit())
+ {
+ string.trim_ascii_start()
+ } else {
+ string
+ }
+}
macro_rules! parser_primitive {
($t:ty) => {
impl Parser for $t {
- fn parse(string: &str) -> Option<Self::Native> {
+ fn parse(mut string: &str) -> Option<Self::Native> {
if !string.as_bytes().last().is_some_and(|x|
x.is_ascii_digit()) {
return None;
}
+ if string
+ .as_bytes()
+ .first()
+ .is_some_and(|first| !first.is_ascii_digit())
+ {
+ string = string.trim_ascii_start();
+ };
match
atoi::FromRadix10SignedChecked::from_radix_10_signed_checked(
string.as_bytes(),
) {
@@ -2872,4 +2894,24 @@ mod tests {
assert_eq!(interval.days, 0);
assert_eq!(interval.nanoseconds, NANOS_PER_SECOND);
}
+ #[test]
+ fn test_parse_prefix_white_space() {
+ assert_eq!(Float64Type::parse(" 1.5"), Some(1.5));
+ assert_eq!(Float64Type::parse("\t\n 20.54"), Some(20.54));
+ assert_eq!(Float64Type::parse("\n2.5"), Some(2.5));
+ assert_eq!(Float64Type::parse("\n-942.5423"), Some(-942.5423));
+ assert_eq!(Float64Type::parse("\n\t\n\t\n40.5123"), Some(40.5123));
+ assert_eq!(Float64Type::parse(" 1.5"), Some(1.5));
+ assert_eq!(Float64Type::parse("\n\t\n\t\n-40.5123"), Some(-40.5123));
+ assert_eq!(Float64Type::parse(" -1.5"), Some(-1.5));
+ assert_eq!(Int32Type::parse(" 3"), Some(3));
+ assert_eq!(Int32Type::parse(" 30"), Some(30));
+ assert_eq!(Int32Type::parse("\n \n 100"), Some(100));
+ assert_eq!(Int32Type::parse(" \n25"), Some(25));
+ assert_eq!(Int32Type::parse("\t800"), Some(800));
+ assert_eq!(Int32Type::parse("\t \n \t 851"), Some(851));
+ assert_eq!(Int32Type::parse("\t\n\t\n\n\n\t1"), Some(1));
+ assert_eq!(Int32Type::parse(" \n-25"), Some(-25));
+ assert_eq!(Int32Type::parse("\t-800"), Some(-800));
+ }
}
