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::cast::as_int64_array;
26use datafusion_common::ScalarValue;
27use datafusion_common::{exec_err, DataFusionError, Result};
28use datafusion_expr::{ColumnarValue, Documentation, TypeSignature, Volatility};
29use datafusion_expr::{ScalarFunctionArgs, ScalarUDFImpl, Signature};
30use datafusion_macros::user_doc;
31use std::any::Any;
32use std::sync::Arc;
33
34#[user_doc(
35    doc_section(label = "String Functions"),
36    description = "Splits a string based on a specified delimiter and returns the substring in the specified position.",
37    syntax_example = "split_part(str, delimiter, pos)",
38    sql_example = r#"```sql
39> select split_part('1.2.3.4.5', '.', 3);
40+--------------------------------------------------+
41| split_part(Utf8("1.2.3.4.5"),Utf8("."),Int64(3)) |
42+--------------------------------------------------+
43| 3                                                |
44+--------------------------------------------------+
45```"#,
46    standard_argument(name = "str", prefix = "String"),
47    argument(name = "delimiter", description = "String or character to split on."),
48    argument(name = "pos", description = "Position of the part to return.")
49)]
50#[derive(Debug)]
51pub struct SplitPartFunc {
52    signature: Signature,
53}
54
55impl Default for SplitPartFunc {
56    fn default() -> Self {
57        Self::new()
58    }
59}
60
61impl SplitPartFunc {
62    pub fn new() -> Self {
63        use DataType::*;
64        Self {
65            signature: Signature::one_of(
66                vec![
67                    TypeSignature::Exact(vec![Utf8View, Utf8View, Int64]),
68                    TypeSignature::Exact(vec![Utf8View, Utf8, Int64]),
69                    TypeSignature::Exact(vec![Utf8View, LargeUtf8, Int64]),
70                    TypeSignature::Exact(vec![Utf8, Utf8View, Int64]),
71                    TypeSignature::Exact(vec![Utf8, Utf8, Int64]),
72                    TypeSignature::Exact(vec![LargeUtf8, Utf8View, Int64]),
73                    TypeSignature::Exact(vec![LargeUtf8, Utf8, Int64]),
74                    TypeSignature::Exact(vec![Utf8, LargeUtf8, Int64]),
75                    TypeSignature::Exact(vec![LargeUtf8, LargeUtf8, Int64]),
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
203/// impl
204pub fn split_part_impl<'a, StringArrType, DelimiterArrType, StringArrayLen>(
205    string_array: StringArrType,
206    delimiter_array: DelimiterArrType,
207    n_array: &Int64Array,
208) -> Result<ArrayRef>
209where
210    StringArrType: StringArrayType<'a>,
211    DelimiterArrType: StringArrayType<'a>,
212    StringArrayLen: OffsetSizeTrait,
213{
214    let mut builder: GenericStringBuilder<StringArrayLen> = GenericStringBuilder::new();
215
216    string_array
217        .iter()
218        .zip(delimiter_array.iter())
219        .zip(n_array.iter())
220        .try_for_each(|((string, delimiter), n)| -> Result<(), DataFusionError> {
221            match (string, delimiter, n) {
222                (Some(string), Some(delimiter), Some(n)) => {
223                    let split_string: Vec<&str> = string.split(delimiter).collect();
224                    let len = split_string.len();
225
226                    let index = match n.cmp(&0) {
227                        std::cmp::Ordering::Less => len as i64 + n,
228                        std::cmp::Ordering::Equal => {
229                            return exec_err!("field position must not be zero");
230                        }
231                        std::cmp::Ordering::Greater => n - 1,
232                    } as usize;
233
234                    if index < len {
235                        builder.append_value(split_string[index]);
236                    } else {
237                        builder.append_value("");
238                    }
239                }
240                _ => builder.append_null(),
241            }
242            Ok(())
243        })?;
244
245    Ok(Arc::new(builder.finish()) as ArrayRef)
246}
247
248#[cfg(test)]
249mod tests {
250    use arrow::array::{Array, StringArray};
251    use arrow::datatypes::DataType::Utf8;
252
253    use datafusion_common::ScalarValue;
254    use datafusion_common::{exec_err, Result};
255    use datafusion_expr::{ColumnarValue, ScalarUDFImpl};
256
257    use crate::string::split_part::SplitPartFunc;
258    use crate::utils::test::test_function;
259
260    #[test]
261    fn test_functions() -> Result<()> {
262        test_function!(
263            SplitPartFunc::new(),
264            vec![
265                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
266                    "abc~@~def~@~ghi"
267                )))),
268                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
269                ColumnarValue::Scalar(ScalarValue::Int64(Some(2))),
270            ],
271            Ok(Some("def")),
272            &str,
273            Utf8,
274            StringArray
275        );
276        test_function!(
277            SplitPartFunc::new(),
278            vec![
279                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
280                    "abc~@~def~@~ghi"
281                )))),
282                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
283                ColumnarValue::Scalar(ScalarValue::Int64(Some(20))),
284            ],
285            Ok(Some("")),
286            &str,
287            Utf8,
288            StringArray
289        );
290        test_function!(
291            SplitPartFunc::new(),
292            vec![
293                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
294                    "abc~@~def~@~ghi"
295                )))),
296                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
297                ColumnarValue::Scalar(ScalarValue::Int64(Some(-1))),
298            ],
299            Ok(Some("ghi")),
300            &str,
301            Utf8,
302            StringArray
303        );
304        test_function!(
305            SplitPartFunc::new(),
306            vec![
307                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from(
308                    "abc~@~def~@~ghi"
309                )))),
310                ColumnarValue::Scalar(ScalarValue::Utf8(Some(String::from("~@~")))),
311                ColumnarValue::Scalar(ScalarValue::Int64(Some(0))),
312            ],
313            exec_err!("field position must not be zero"),
314            &str,
315            Utf8,
316            StringArray
317        );
318
319        Ok(())
320    }
321}
datafusion_functions/string/split_part.rs

datafusion_functions/string/
split_part.rs
