datafusion_functions/string/
split_part.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use crate::utils::utf8_to_str_type;
19use arrow::array::{
20    ArrayRef, GenericStringArray, Int64Array, OffsetSizeTrait, StringArrayType,
21    StringViewArray,
22};
23use arrow::array::{AsArray, GenericStringBuilder};
24use arrow::datatypes::DataType;
25use datafusion_common::ScalarValue;
26use datafusion_common::cast::as_int64_array;
27use datafusion_common::types::{NativeType, logical_int64, logical_string};
28use datafusion_common::{DataFusionError, Result, exec_err};
29use datafusion_expr::{
30    Coercion, ColumnarValue, Documentation, TypeSignatureClass, Volatility,
31};
32use datafusion_expr::{ScalarFunctionArgs, ScalarUDFImpl, Signature};
33use datafusion_macros::user_doc;
34use std::any::Any;
35use std::sync::Arc;
36
37#[user_doc(
38    doc_section(label = "String Functions"),
39    description = "Splits a string based on a specified delimiter and returns the substring in the specified position.",
40    syntax_example = "split_part(str, delimiter, pos)",
41    sql_example = r#"```sql
42> select split_part('1.2.3.4.5', '.', 3);
43+--------------------------------------------------+
44| split_part(Utf8("1.2.3.4.5"),Utf8("."),Int64(3)) |
45+--------------------------------------------------+
46| 3                                                |
47+--------------------------------------------------+
48```"#,
49    standard_argument(name = "str", prefix = "String"),
50    argument(name = "delimiter", description = "String or character to split on."),
51    argument(name = "pos", description = "Position of the part to return.")
52)]
53#[derive(Debug, PartialEq, Eq, Hash)]
54pub struct SplitPartFunc {
55    signature: Signature,
56}
57
58impl Default for SplitPartFunc {
59    fn default() -> Self {
60        Self::new()
61    }
62}
63
64impl SplitPartFunc {
65    pub fn new() -> Self {
66        Self {
67            signature: Signature::coercible(
68                vec![
69                    Coercion::new_exact(TypeSignatureClass::Native(logical_string())),
70                    Coercion::new_exact(TypeSignatureClass::Native(logical_string())),
71                    Coercion::new_implicit(
72                        TypeSignatureClass::Native(logical_int64()),
73                        vec![TypeSignatureClass::Integer],
74                        NativeType::Int64,
75                    ),
76                ],
77                Volatility::Immutable,
78            ),
79        }
80    }
81}
82
83impl ScalarUDFImpl for SplitPartFunc {
84    fn as_any(&self) -> &dyn Any {
85        self
86    }
87
88    fn name(&self) -> &str {
89        "split_part"
90    }
91
92    fn signature(&self) -> &Signature {
93        &self.signature
94    }
95
96    fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> {
97        utf8_to_str_type(&arg_types[0], "split_part")
98    }
99
100    fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> {
101        let ScalarFunctionArgs { args, .. } = args;
102
103        // First, determine if any of the arguments is an Array
104        let len = args.iter().find_map(|arg| match arg {
105            ColumnarValue::Array(a) => Some(a.len()),
106            _ => None,
107        });
108
109        let inferred_length = len.unwrap_or(1);
110        let is_scalar = len.is_none();
111
112        // Convert all ColumnarValues to ArrayRefs
113        let args = args
114            .iter()
115            .map(|arg| match arg {
116                ColumnarValue::Scalar(scalar) => scalar.to_array_of_size(inferred_length),
117                ColumnarValue::Array(array) => Ok(Arc::clone(array)),
118            })
119            .collect::<Result<Vec<_>>>()?;
120
121        // Unpack the ArrayRefs from the arguments
122        let n_array = as_int64_array(&args[2])?;
123        let result = match (args[0].data_type(), args[1].data_type()) {
124            (DataType::Utf8View, DataType::Utf8View) => {
125                split_part_impl::<&StringViewArray, &StringViewArray, i32>(
126                    &args[0].as_string_view(),
127                    &args[1].as_string_view(),
128                    n_array,
129                )
130            }
131            (DataType::Utf8View, DataType::Utf8) => {
132                split_part_impl::<&StringViewArray, &GenericStringArray<i32>, i32>(
133                    &args[0].as_string_view(),
134                    &args[1].as_string::<i32>(),
135                    n_array,
136                )
137            }
138            (DataType::Utf8View, DataType::LargeUtf8) => {
139                split_part_impl::<&StringViewArray, &GenericStringArray<i64>, i32>(
140                    &args[0].as_string_view(),
141                    &args[1].as_string::<i64>(),
142                    n_array,
143                )
144            }
145            (DataType::Utf8, DataType::Utf8View) => {
146                split_part_impl::<&GenericStringArray<i32>, &StringViewArray, i32>(
147                    &args[0].as_string::<i32>(),
148                    &args[1].as_string_view(),
149                    n_array,
150                )
151            }
152            (DataType::LargeUtf8, DataType::Utf8View) => {
153                split_part_impl::<&GenericStringArray<i64>, &StringViewArray, i64>(
154                    &args[0].as_string::<i64>(),
155                    &args[1].as_string_view(),
156                    n_array,
157                )
158            }
159            (DataType::Utf8, DataType::Utf8) => {
160                split_part_impl::<&GenericStringArray<i32>, &GenericStringArray<i32>, i32>(
161                    &args[0].as_string::<i32>(),
162                    &args[1].as_string::<i32>(),
163                    n_array,
164                )
165            }
166            (DataType::LargeUtf8, DataType::LargeUtf8) => {
167                split_part_impl::<&GenericStringArray<i64>, &GenericStringArray<i64>, i64>(
168                    &args[0].as_string::<i64>(),
169                    &args[1].as_string::<i64>(),
170                    n_array,
171                )
172            }
173            (DataType::Utf8, DataType::LargeUtf8) => {
174                split_part_impl::<&GenericStringArray<i32>, &GenericStringArray<i64>, i32>(
175                    &args[0].as_string::<i32>(),
176                    &args[1].as_string::<i64>(),
177                    n_array,
178                )
179            }
180            (DataType::LargeUtf8, DataType::Utf8) => {
181                split_part_impl::<&GenericStringArray<i64>, &GenericStringArray<i32>, i64>(
182                    &args[0].as_string::<i64>(),
183                    &args[1].as_string::<i32>(),
184                    n_array,
185                )
186            }
187            _ => exec_err!("Unsupported combination of argument types for split_part"),
188        };
189        if is_scalar {
190            // If all inputs are scalar, keep the output as scalar
191            let result = result.and_then(|arr| ScalarValue::try_from_array(&arr, 0));
192            result.map(ColumnarValue::Scalar)
193        } else {
194            result.map(ColumnarValue::Array)
195        }
196    }
197
198    fn documentation(&self) -> Option<&Documentation> {
199        self.doc()
200    }
201}
202
203fn split_part_impl<'a, StringArrType, DelimiterArrType, StringArrayLen>(
204    string_array: &StringArrType,
205    delimiter_array: &DelimiterArrType,
206    n_array: &Int64Array,
207) -> Result<ArrayRef>
208where
209    StringArrType: StringArrayType<'a>,
210    DelimiterArrType: StringArrayType<'a>,
211    StringArrayLen: OffsetSizeTrait,
212{
213    let mut builder: GenericStringBuilder<StringArrayLen> = GenericStringBuilder::new();
214
215    string_array
216        .iter()
217        .zip(delimiter_array.iter())
218        .zip(n_array.iter())
219        .try_for_each(|((string, delimiter), n)| -> Result<(), DataFusionError> {
220            match (string, delimiter, n) {
221                (Some(string), Some(delimiter), Some(n)) => {
222                    let split_string: Vec<&str> = string.split(delimiter).collect();
223                    let len = split_string.len();
224
225                    let index = match n.cmp(&0) {
226                        std::cmp::Ordering::Less => len as i64 + n,
227                        std::cmp::Ordering::Equal => {
228                            return exec_err!("field position must not be zero");
229                        }
230                        std::cmp::Ordering::Greater => n - 1,
231                    } as usize;
232
233                    if index < len {
234                        builder.append_value(split_string[index]);
235                    } else {
236                        builder.append_value("");
237                    }
238                }
239                _ => builder.append_null(),
240            }
241            Ok(())
242        })?;
243
244    Ok(Arc::new(builder.finish()) as ArrayRef)
245}
246
247#[cfg(test)]
248mod tests {
249    use arrow::array::{Array, StringArray};
250    use arrow::datatypes::DataType::Utf8;
251
252    use datafusion_common::ScalarValue;
253    use datafusion_common::{Result, exec_err};
254    use datafusion_expr::{ColumnarValue, ScalarUDFImpl};
255
256    use crate::string::split_part::SplitPartFunc;
257    use crate::utils::test::test_function;
258
259    #[test]
260    fn test_functions() -> Result<()> {
261        test_function!(
262            SplitPartFunc::new(),
263            vec![
264                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
265                    "abc~@~def~@~ghi"
266                )))),
267                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
268                ColumnarValue::Scalar(ScalarValue::Int64(Some(2))),
269            ],
270            Ok(Some("def")),
271            &str,
272            Utf8,
273            StringArray
274        );
275        test_function!(
276            SplitPartFunc::new(),
277            vec![
278                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
279                    "abc~@~def~@~ghi"
280                )))),
281                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
282                ColumnarValue::Scalar(ScalarValue::Int64(Some(20))),
283            ],
284            Ok(Some("")),
285            &str,
286            Utf8,
287            StringArray
288        );
289        test_function!(
290            SplitPartFunc::new(),
291            vec![
292                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
293                    "abc~@~def~@~ghi"
294                )))),
295                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
296                ColumnarValue::Scalar(ScalarValue::Int64(Some(-1))),
297            ],
298            Ok(Some("ghi")),
299            &str,
300            Utf8,
301            StringArray
302        );
303        test_function!(
304            SplitPartFunc::new(),
305            vec![
306                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
307                    "abc~@~def~@~ghi"
308                )))),
309                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
310                ColumnarValue::Scalar(ScalarValue::Int64(Some(0))),
311            ],
312            exec_err!("field position must not be zero"),
313            &str,
314            Utf8,
315            StringArray
316        );
317
318        Ok(())
319    }
320}
datafusion_functions/string/split_part.rs

datafusion_functions/string/
split_part.rs
