diff --git a/polars/polars-core/src/chunked_array/bitwise.rs b/polars/polars-core/src/chunked_array/bitwise.rs
index 3640343a6762..3a59a548b5cf 100644
--- a/polars/polars-core/src/chunked_array/bitwise.rs
+++ b/polars/polars-core/src/chunked_array/bitwise.rs
@@ -117,14 +117,14 @@ impl BitOr for &BooleanChunked {
                         rhs.rename(self.name());
                         rhs
                     }
-                    None => &self.expand_at_index(0, rhs.len()) | rhs,
+                    None => &self.new_from_index(0, rhs.len()) | rhs,
                 };
             }
             (_, 1) => {
                 return match rhs.get(0) {
                     Some(true) => BooleanChunked::full(self.name(), true, self.len()),
                     Some(false) => self.clone(),
-                    None => &rhs.expand_at_index(0, self.len()) | self,
+                    None => &rhs.new_from_index(0, self.len()) | self,
                 };
             }
             _ => {}
@@ -168,14 +168,14 @@ impl BitXor for &BooleanChunked {
                         rhs.rename(self.name());
                         rhs
                     }
-                    None => &self.expand_at_index(0, rhs.len()) | rhs,
+                    None => &self.new_from_index(0, rhs.len()) | rhs,
                 };
             }
             (_, 1) => {
                 return match rhs.get(0) {
                     Some(true) => self.not(),
                     Some(false) => self.clone(),
-                    None => &rhs.expand_at_index(0, self.len()) | self,
+                    None => &rhs.new_from_index(0, self.len()) | self,
                 };
             }
             _ => {}
@@ -218,14 +218,14 @@ impl BitAnd for &BooleanChunked {
                 return match self.get(0) {
                     Some(true) => rhs.clone(),
                     Some(false) => BooleanChunked::full(self.name(), false, rhs.len()),
-                    None => &self.expand_at_index(0, rhs.len()) & rhs,
+                    None => &self.new_from_index(0, rhs.len()) & rhs,
                 };
             }
             (_, 1) => {
                 return match rhs.get(0) {
                     Some(true) => self.clone(),
                     Some(false) => BooleanChunked::full(self.name(), false, self.len()),
-                    None => self & &rhs.expand_at_index(0, self.len()),
+                    None => self & &rhs.new_from_index(0, self.len()),
                 };
             }
             _ => {}
diff --git a/polars/polars-core/src/chunked_array/logical/struct_/mod.rs b/polars/polars-core/src/chunked_array/logical/struct_/mod.rs
index 53dd8a9c1a25..1ca4c45d44a9 100644
--- a/polars/polars-core/src/chunked_array/logical/struct_/mod.rs
+++ b/polars/polars-core/src/chunked_array/logical/struct_/mod.rs
@@ -55,7 +55,7 @@ impl StructChunked {
                 if s_len == max_len {
                     new_fields.push(s.clone())
                 } else if s_len == 1 {
-                    new_fields.push(s.expand_at_index(0, max_len))
+                    new_fields.push(s.new_from_index(0, max_len))
                 } else {
                     return Err(PolarsError::ShapeMisMatch(
                         "expected all fields to have equal length".into(),
diff --git a/polars/polars-core/src/chunked_array/ops/mod.rs b/polars/polars-core/src/chunked_array/ops/mod.rs
index 3f441c509011..9593c5faf5d6 100644
--- a/polars/polars-core/src/chunked_array/ops/mod.rs
+++ b/polars/polars-core/src/chunked_array/ops/mod.rs
@@ -601,7 +601,7 @@ pub trait ChunkFilter<T: PolarsDataType> {
 /// Create a new ChunkedArray filled with values at that index.
 pub trait ChunkExpandAtIndex<T: PolarsDataType> {
     /// Create a new ChunkedArray filled with values at that index.
-    fn expand_at_index(&self, length: usize, index: usize) -> ChunkedArray<T>;
+    fn new_from_index(&self, length: usize, index: usize) -> ChunkedArray<T>;
 }
 
 macro_rules! impl_chunk_expand {
@@ -622,32 +622,32 @@ where
     ChunkedArray<T>: ChunkFull<T::Native> + TakeRandom<Item = T::Native>,
     T: PolarsNumericType,
 {
-    fn expand_at_index(&self, index: usize, length: usize) -> ChunkedArray<T> {
+    fn new_from_index(&self, index: usize, length: usize) -> ChunkedArray<T> {
         impl_chunk_expand!(self, length, index)
     }
 }
 
 impl ChunkExpandAtIndex<BooleanType> for BooleanChunked {
-    fn expand_at_index(&self, index: usize, length: usize) -> BooleanChunked {
+    fn new_from_index(&self, index: usize, length: usize) -> BooleanChunked {
         impl_chunk_expand!(self, length, index)
     }
 }
 
 impl ChunkExpandAtIndex<Utf8Type> for Utf8Chunked {
-    fn expand_at_index(&self, index: usize, length: usize) -> Utf8Chunked {
+    fn new_from_index(&self, index: usize, length: usize) -> Utf8Chunked {
         impl_chunk_expand!(self, length, index)
     }
 }
 
 #[cfg(feature = "dtype-binary")]
 impl ChunkExpandAtIndex<BinaryType> for BinaryChunked {
-    fn expand_at_index(&self, index: usize, length: usize) -> BinaryChunked {
+    fn new_from_index(&self, index: usize, length: usize) -> BinaryChunked {
         impl_chunk_expand!(self, length, index)
     }
 }
 
 impl ChunkExpandAtIndex<ListType> for ListChunked {
-    fn expand_at_index(&self, index: usize, length: usize) -> ListChunked {
+    fn new_from_index(&self, index: usize, length: usize) -> ListChunked {
         let opt_val = self.get(index);
         match opt_val {
             Some(val) => ListChunked::full(self.name(), &val, length),
@@ -658,7 +658,7 @@ impl ChunkExpandAtIndex<ListType> for ListChunked {
 
 #[cfg(feature = "object")]
 impl<T: PolarsObject> ChunkExpandAtIndex<ObjectType<T>> for ObjectChunked<T> {
-    fn expand_at_index(&self, index: usize, length: usize) -> ObjectChunked<T> {
+    fn new_from_index(&self, index: usize, length: usize) -> ObjectChunked<T> {
         let opt_val = self.get(index);
         match opt_val {
             Some(val) => ObjectChunked::<T>::full(self.name(), val.clone(), length),
diff --git a/polars/polars-core/src/doc/changelog/v0_7.rs b/polars/polars-core/src/doc/changelog/v0_7.rs
index 935f6bc3d033..4d13947ac46e 100644
--- a/polars/polars-core/src/doc/changelog/v0_7.rs
+++ b/polars/polars-core/src/doc/changelog/v0_7.rs
@@ -13,7 +13,7 @@
 //! * Rem trait implemented for Series and ChunkedArrays
 //! * ChunkedArrays broadcasting arithmetic
 //! * ChunkedArray/Series `zip_with` operation
-//! * ChunkedArray/Series `expand_at_index` operation
+//! * ChunkedArray/Series `new_from_index` operation
 //! * laziness api initiated.
 //!     - Predicate pushdown optimizer
 //!     - Projection pushdown optimizer
diff --git a/polars/polars-core/src/frame/arithmetic.rs b/polars/polars-core/src/frame/arithmetic.rs
index bed5d785c7c3..c0c2150e694a 100644
--- a/polars/polars-core/src/frame/arithmetic.rs
+++ b/polars/polars-core/src/frame/arithmetic.rs
@@ -150,7 +150,7 @@ impl DataFrame {
                 // trick to fill a series with nulls
                 let vals: &[Option<i32>] = &[None];
                 let s = Series::new(name, vals).cast(dtype)?;
-                cols.push(s.expand_at_index(0, max_len))
+                cols.push(s.new_from_index(0, max_len))
             }
         }
         DataFrame::new(cols)
diff --git a/polars/polars-core/src/frame/mod.rs b/polars/polars-core/src/frame/mod.rs
index 262645631f75..3c3483936c41 100644
--- a/polars/polars-core/src/frame/mod.rs
+++ b/polars/polars-core/src/frame/mod.rs
@@ -1115,7 +1115,7 @@ impl DataFrame {
         fn inner(df: &mut DataFrame, mut series: Series) -> PolarsResult<&mut DataFrame> {
             let height = df.height();
             if series.len() == 1 && height > 1 {
-                series = series.expand_at_index(0, height);
+                series = series.new_from_index(0, height);
             }
 
             if series.len() == height || df.is_empty() {
@@ -1169,7 +1169,7 @@ impl DataFrame {
 
         let height = self.height();
         if series.len() == 1 && height > 1 {
-            series = series.expand_at_index(0, height);
+            series = series.new_from_index(0, height);
         }
 
         if series.len() == height || self.is_empty() {
@@ -2042,7 +2042,7 @@ impl DataFrame {
         let new_col = f(col).into_series();
         match new_col.len() {
             1 => {
-                let new_col = new_col.expand_at_index(0, df_height);
+                let new_col = new_col.new_from_index(0, df_height);
                 let _ = mem::replace(col, new_col);
             }
             len if (len == df_height) => {
diff --git a/polars/polars-core/src/functions.rs b/polars/polars-core/src/functions.rs
index 19ae824c8c41..8fd93b828e42 100644
--- a/polars/polars-core/src/functions.rs
+++ b/polars/polars-core/src/functions.rs
@@ -156,7 +156,7 @@ pub fn concat_str(s: &[Series], delimiter: &str) -> PolarsResult<Utf8Chunked> {
             let mut ca = s.utf8()?.clone();
             // broadcast
             if ca.len() == 1 && len > 1 {
-                ca = ca.expand_at_index(0, len)
+                ca = ca.new_from_index(0, len)
             }
 
             Ok(ca)
diff --git a/polars/polars-core/src/series/implementations/binary.rs b/polars/polars-core/src/series/implementations/binary.rs
index 8a4f7e81e8c2..54029d148f7f 100644
--- a/polars/polars-core/src/series/implementations/binary.rs
+++ b/polars/polars-core/src/series/implementations/binary.rs
@@ -227,8 +227,8 @@ impl SeriesTrait for SeriesWrap<BinaryChunked> {
         self.0.rechunk().into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
-        ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
+        ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
     }
 
     fn cast(&self, data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/implementations/boolean.rs b/polars/polars-core/src/series/implementations/boolean.rs
index 7cbcb2a4c4f9..62b3f9452f80 100644
--- a/polars/polars-core/src/series/implementations/boolean.rs
+++ b/polars/polars-core/src/series/implementations/boolean.rs
@@ -237,8 +237,8 @@ impl SeriesTrait for SeriesWrap<BooleanChunked> {
         self.0.rechunk().into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
-        ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
+        ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
     }
 
     fn cast(&self, data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/implementations/categorical.rs b/polars/polars-core/src/series/implementations/categorical.rs
index 7e00596330e4..97e70636b536 100644
--- a/polars/polars-core/src/series/implementations/categorical.rs
+++ b/polars/polars-core/src/series/implementations/categorical.rs
@@ -285,8 +285,8 @@ impl SeriesTrait for SeriesWrap<CategoricalChunked> {
         self.with_state(true, |ca| ca.rechunk()).into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
-        self.with_state(true, |cats| cats.expand_at_index(index, length))
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
+        self.with_state(true, |cats| cats.new_from_index(index, length))
             .into_series()
     }
 
diff --git a/polars/polars-core/src/series/implementations/dates_time.rs b/polars/polars-core/src/series/implementations/dates_time.rs
index d1e90f211777..66d9b751ecfb 100644
--- a/polars/polars-core/src/series/implementations/dates_time.rs
+++ b/polars/polars-core/src/series/implementations/dates_time.rs
@@ -326,9 +326,9 @@ macro_rules! impl_dyn_series {
                 self.0.rechunk().$into_logical().into_series()
             }
 
-            fn expand_at_index(&self, index: usize, length: usize) -> Series {
+            fn new_from_index(&self, index: usize, length: usize) -> Series {
                 self.0
-                    .expand_at_index(index, length)
+                    .new_from_index(index, length)
                     .$into_logical()
                     .into_series()
             }
diff --git a/polars/polars-core/src/series/implementations/datetime.rs b/polars/polars-core/src/series/implementations/datetime.rs
index 886dd0b964f7..fe17f6cddaeb 100644
--- a/polars/polars-core/src/series/implementations/datetime.rs
+++ b/polars/polars-core/src/series/implementations/datetime.rs
@@ -352,9 +352,9 @@ impl SeriesTrait for SeriesWrap<DatetimeChunked> {
             .into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
         self.0
-            .expand_at_index(index, length)
+            .new_from_index(index, length)
             .into_datetime(self.0.time_unit(), self.0.time_zone().clone())
             .into_series()
     }
diff --git a/polars/polars-core/src/series/implementations/duration.rs b/polars/polars-core/src/series/implementations/duration.rs
index 47d58dc0c0b0..53d33e2c62a4 100644
--- a/polars/polars-core/src/series/implementations/duration.rs
+++ b/polars/polars-core/src/series/implementations/duration.rs
@@ -369,9 +369,9 @@ impl SeriesTrait for SeriesWrap<DurationChunked> {
             .into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
         self.0
-            .expand_at_index(index, length)
+            .new_from_index(index, length)
             .into_duration(self.0.time_unit())
             .into_series()
     }
diff --git a/polars/polars-core/src/series/implementations/floats.rs b/polars/polars-core/src/series/implementations/floats.rs
index ce09a5950a2f..782870496bbc 100644
--- a/polars/polars-core/src/series/implementations/floats.rs
+++ b/polars/polars-core/src/series/implementations/floats.rs
@@ -293,8 +293,8 @@ macro_rules! impl_dyn_series {
                 self.0.rechunk().into_series()
             }
 
-            fn expand_at_index(&self, index: usize, length: usize) -> Series {
-                ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+            fn new_from_index(&self, index: usize, length: usize) -> Series {
+                ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
             }
 
             fn cast(&self, data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/implementations/list.rs b/polars/polars-core/src/series/implementations/list.rs
index a6ad67f606b3..d847c01a3cb4 100644
--- a/polars/polars-core/src/series/implementations/list.rs
+++ b/polars/polars-core/src/series/implementations/list.rs
@@ -159,8 +159,8 @@ impl SeriesTrait for SeriesWrap<ListChunked> {
         self.0.rechunk().into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
-        ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
+        ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
     }
 
     fn cast(&self, data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/implementations/mod.rs b/polars/polars-core/src/series/implementations/mod.rs
index 1746ff7d6bb0..05e7d9487428 100644
--- a/polars/polars-core/src/series/implementations/mod.rs
+++ b/polars/polars-core/src/series/implementations/mod.rs
@@ -381,8 +381,8 @@ macro_rules! impl_dyn_series {
                 self.0.rechunk().into_series()
             }
 
-            fn expand_at_index(&self, index: usize, length: usize) -> Series {
-                ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+            fn new_from_index(&self, index: usize, length: usize) -> Series {
+                ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
             }
 
             fn cast(&self, data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/implementations/object.rs b/polars/polars-core/src/series/implementations/object.rs
index 7b62d3dd4ca4..d1b54d9b6c04 100644
--- a/polars/polars-core/src/series/implementations/object.rs
+++ b/polars/polars-core/src/series/implementations/object.rs
@@ -173,8 +173,8 @@ where
         self.0.take_every(n).into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
-        ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
+        ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
     }
 
     fn cast(&self, _data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/implementations/struct_.rs b/polars/polars-core/src/series/implementations/struct_.rs
index 985307e76dd4..39cd1ae4c275 100644
--- a/polars/polars-core/src/series/implementations/struct_.rs
+++ b/polars/polars-core/src/series/implementations/struct_.rs
@@ -235,9 +235,9 @@ impl SeriesTrait for SeriesWrap<StructChunked> {
         out.into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
         self.0
-            .apply_fields(|s| s.expand_at_index(index, length))
+            .apply_fields(|s| s.new_from_index(index, length))
             .into_series()
     }
 
diff --git a/polars/polars-core/src/series/implementations/utf8.rs b/polars/polars-core/src/series/implementations/utf8.rs
index f49191fbd1e0..761574e6a7cc 100644
--- a/polars/polars-core/src/series/implementations/utf8.rs
+++ b/polars/polars-core/src/series/implementations/utf8.rs
@@ -227,8 +227,8 @@ impl SeriesTrait for SeriesWrap<Utf8Chunked> {
         self.0.rechunk().into_series()
     }
 
-    fn expand_at_index(&self, index: usize, length: usize) -> Series {
-        ChunkExpandAtIndex::expand_at_index(&self.0, index, length).into_series()
+    fn new_from_index(&self, index: usize, length: usize) -> Series {
+        ChunkExpandAtIndex::new_from_index(&self.0, index, length).into_series()
     }
 
     fn cast(&self, data_type: &DataType) -> PolarsResult<Series> {
diff --git a/polars/polars-core/src/series/ops/extend.rs b/polars/polars-core/src/series/ops/extend.rs
index b1eee5a84c0d..1872d5110c52 100644
--- a/polars/polars-core/src/series/ops/extend.rs
+++ b/polars/polars-core/src/series/ops/extend.rs
@@ -17,7 +17,7 @@ impl Series {
             dt => panic!("{:?} not supported", dt),
         };
         let s = s.cast(self.dtype())?;
-        let to_append = s.expand_at_index(0, n);
+        let to_append = s.new_from_index(0, n);
 
         let mut out = self.clone();
         out.append(&to_append)?;
diff --git a/polars/polars-core/src/series/series_trait.rs b/polars/polars-core/src/series/series_trait.rs
index 682c960bbcba..5bc7fe60269a 100644
--- a/polars/polars-core/src/series/series_trait.rs
+++ b/polars/polars-core/src/series/series_trait.rs
@@ -381,17 +381,17 @@ pub trait SeriesTrait:
         None
     }
 
-    /// Create a new Series filled with values at that index.
+    /// Create a new Series filled with values from the given index.
     ///
     /// # Example
     ///
     /// ```rust
     /// use polars_core::prelude::*;
     /// let s = Series::new("a", [0i32, 1, 8]);
-    /// let expanded = s.expand_at_index(2, 4);
-    /// assert_eq!(Vec::from(expanded.i32().unwrap()), &[Some(8), Some(8), Some(8), Some(8)])
+    /// let s2 = s.new_from_index(2, 4);
+    /// assert_eq!(Vec::from(s2.i32().unwrap()), &[Some(8), Some(8), Some(8), Some(8)])
     /// ```
-    fn expand_at_index(&self, _index: usize, _length: usize) -> Series {
+    fn new_from_index(&self, _index: usize, _length: usize) -> Series {
         invalid_operation_panic!(self)
     }
 
diff --git a/polars/polars-lazy/polars-plan/src/dsl/functions.rs b/polars/polars-lazy/polars-plan/src/dsl/functions.rs
index 75e9efad2f8a..7ddb695fad72 100644
--- a/polars/polars-lazy/polars-plan/src/dsl/functions.rs
+++ b/polars/polars-lazy/polars-plan/src/dsl/functions.rs
@@ -422,40 +422,40 @@ pub fn datetime(args: DatetimeArgs) -> Expr {
         let max_len = s.iter().map(|s| s.len()).max().unwrap();
         let mut year = s[0].cast(&DataType::Int32)?;
         if year.len() < max_len {
-            year = year.expand_at_index(0, max_len)
+            year = year.new_from_index(0, max_len)
         }
         let year = year.i32()?;
         let mut month = s[1].cast(&DataType::UInt32)?;
         if month.len() < max_len {
-            month = month.expand_at_index(0, max_len);
+            month = month.new_from_index(0, max_len);
         }
         let month = month.u32()?;
         let mut day = s[2].cast(&DataType::UInt32)?;
         if day.len() < max_len {
-            day = day.expand_at_index(0, max_len);
+            day = day.new_from_index(0, max_len);
         }
         let day = day.u32()?;
         let mut hour = s[3].cast(&DataType::UInt32)?;
         if hour.len() < max_len {
-            hour = hour.expand_at_index(0, max_len);
+            hour = hour.new_from_index(0, max_len);
         }
         let hour = hour.u32()?;
 
         let mut minute = s[4].cast(&DataType::UInt32)?;
         if minute.len() < max_len {
-            minute = minute.expand_at_index(0, max_len);
+            minute = minute.new_from_index(0, max_len);
         }
         let minute = minute.u32()?;
 
         let mut second = s[5].cast(&DataType::UInt32)?;
         if second.len() < max_len {
-            second = second.expand_at_index(0, max_len);
+            second = second.new_from_index(0, max_len);
         }
         let second = second.u32()?;
 
         let mut microsecond = s[6].cast(&DataType::UInt32)?;
         if microsecond.len() < max_len {
-            microsecond = microsecond.expand_at_index(0, max_len);
+            microsecond = microsecond.new_from_index(0, max_len);
         }
         let microsecond = microsecond.u32()?;
 
@@ -540,7 +540,7 @@ pub fn duration(args: DurationArgs) -> Expr {
         };
 
         if nanoseconds.len() != max_len {
-            nanoseconds = nanoseconds.expand_at_index(0, max_len);
+            nanoseconds = nanoseconds.new_from_index(0, max_len);
         }
         if condition(&microseconds) {
             nanoseconds = nanoseconds + (microseconds * 1_000);
@@ -947,7 +947,7 @@ pub fn repeat<L: Literal>(value: L, n_times: Expr) -> Expr {
         let n = n.get(0).extract::<usize>().ok_or_else(|| {
             PolarsError::ComputeError(format!("could not extract a size from {:?}", n).into())
         })?;
-        Ok(s.expand_at_index(0, n))
+        Ok(s.new_from_index(0, n))
     };
     apply_binary(lit(value), n_times, function, GetOutput::same_type())
 }
diff --git a/polars/polars-lazy/src/physical_plan/executors/groupby_partitioned.rs b/polars/polars-lazy/src/physical_plan/executors/groupby_partitioned.rs
index 0822d13d3c2c..e45add213275 100644
--- a/polars/polars-lazy/src/physical_plan/executors/groupby_partitioned.rs
+++ b/polars/polars-lazy/src/physical_plan/executors/groupby_partitioned.rs
@@ -80,7 +80,7 @@ fn run_partitions(
                             if agg.len() == 1 {
                                 Ok(match groups.len()  {
                                     0 => agg.slice(0, 0),
-                                    len => agg.expand_at_index(0, len)
+                                    len => agg.new_from_index(0, len)
                                 })
                             } else {
                                 Err(PolarsError::ComputeError(
diff --git a/polars/polars-lazy/src/physical_plan/executors/mod.rs b/polars/polars-lazy/src/physical_plan/executors/mod.rs
index 706d23339776..0de4750859b2 100644
--- a/polars/polars-lazy/src/physical_plan/executors/mod.rs
+++ b/polars/polars-lazy/src/physical_plan/executors/mod.rs
@@ -206,7 +206,7 @@ fn check_expand_literals(
             .into_iter()
             .map(|series| {
                 if series.len() == 1 && df_height > 1 {
-                    Ok(series.expand_at_index(0, df_height))
+                    Ok(series.new_from_index(0, df_height))
                 } else if series.len() == df_height || series.len() == 0 {
                     Ok(series)
                 } else {
diff --git a/polars/polars-lazy/src/physical_plan/expressions/mod.rs b/polars/polars-lazy/src/physical_plan/expressions/mod.rs
index 881af996ede8..19655d78e2d0 100644
--- a/polars/polars-lazy/src/physical_plan/expressions/mod.rs
+++ b/polars/polars-lazy/src/physical_plan/expressions/mod.rs
@@ -418,7 +418,7 @@ impl<'a> AggregationContext<'a> {
             AggState::Literal(s) => {
                 self.groups();
                 let rows = self.groups.len();
-                let s = s.expand_at_index(0, rows);
+                let s = s.new_from_index(0, rows);
                 s.reshape(&[rows as i64, -1]).unwrap()
             }
         }
@@ -433,7 +433,7 @@ impl<'a> AggregationContext<'a> {
                 let s = s.clone();
                 self.groups();
                 let rows = self.groups.len();
-                s.expand_at_index(0, rows)
+                s.new_from_index(0, rows)
             }
             _ => self.aggregated(),
         }
@@ -465,7 +465,7 @@ impl<'a> AggregationContext<'a> {
                 // we allocated enough
                 unsafe { offsets.push_unchecked(last_offset) };
             }
-            let values = s.expand_at_index(0, last_offset as usize);
+            let values = s.new_from_index(0, last_offset as usize);
             let values = values.array_ref(0).clone();
             // Safety:
             // offsets are monotonically increasing
diff --git a/polars/polars-lazy/src/physical_plan/expressions/ternary.rs b/polars/polars-lazy/src/physical_plan/expressions/ternary.rs
index a384756334c3..65721b4b5245 100644
--- a/polars/polars-lazy/src/physical_plan/expressions/ternary.rs
+++ b/polars/polars-lazy/src/physical_plan/expressions/ternary.rs
@@ -35,13 +35,13 @@ fn expand_lengths(truthy: &mut Series, falsy: &mut Series, mask: &mut BooleanChu
     let len = std::cmp::max(std::cmp::max(truthy.len(), falsy.len()), mask.len());
     if len > 1 {
         if falsy.len() == 1 {
-            *falsy = falsy.expand_at_index(0, len);
+            *falsy = falsy.new_from_index(0, len);
         }
         if truthy.len() == 1 {
-            *truthy = truthy.expand_at_index(0, len);
+            *truthy = truthy.new_from_index(0, len);
         }
         if mask.len() == 1 {
-            *mask = mask.expand_at_index(0, len);
+            *mask = mask.new_from_index(0, len);
         }
     }
 }
diff --git a/polars/polars-ops/src/chunked_array/list/namespace.rs b/polars/polars-ops/src/chunked_array/list/namespace.rs
index 45a4a0c50c51..ec7949912bfb 100644
--- a/polars/polars-ops/src/chunked_array/list/namespace.rs
+++ b/polars/polars-ops/src/chunked_array/list/namespace.rs
@@ -42,7 +42,7 @@ fn cast_rhs(
             if s.len() == 1 {
                 if allow_broadcast {
                     // broadcast JIT
-                    *s = s.expand_at_index(0, length)
+                    *s = s.new_from_index(0, length)
                 }
                 // else do nothing
             } else {