datafusion_functions/unicode/
strpos.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 std::any::Any;
19use std::sync::Arc;
20
21use crate::utils::{make_scalar_function, utf8_to_int_type};
22use arrow::array::{
23    ArrayRef, ArrowPrimitiveType, AsArray, PrimitiveArray, StringArrayType,
24};
25use arrow::datatypes::{
26    ArrowNativeType, DataType, Field, FieldRef, Int32Type, Int64Type,
27};
28use datafusion_common::types::logical_string;
29use datafusion_common::{exec_err, internal_err, Result};
30use datafusion_expr::{
31    Coercion, ColumnarValue, Documentation, ScalarUDFImpl, Signature, TypeSignatureClass,
32    Volatility,
33};
34use datafusion_macros::user_doc;
35
36#[user_doc(
37    doc_section(label = "String Functions"),
38    description = "Returns the starting position of a specified substring in a string. Positions begin at 1. If the substring does not exist in the string, the function returns 0.",
39    syntax_example = "strpos(str, substr)",
40    alternative_syntax = "position(substr in origstr)",
41    sql_example = r#"```sql
42> select strpos('datafusion', 'fus');
43+----------------------------------------+
44| strpos(Utf8("datafusion"),Utf8("fus")) |
45+----------------------------------------+
46| 5                                      |
47+----------------------------------------+ 
48```"#,
49    standard_argument(name = "str", prefix = "String"),
50    argument(name = "substr", description = "Substring expression to search for.")
51)]
52#[derive(Debug)]
53pub struct StrposFunc {
54    signature: Signature,
55    aliases: Vec<String>,
56}
57
58impl Default for StrposFunc {
59    fn default() -> Self {
60        Self::new()
61    }
62}
63
64impl StrposFunc {
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                ],
72                Volatility::Immutable,
73            ),
74            aliases: vec![String::from("instr"), String::from("position")],
75        }
76    }
77}
78
79impl ScalarUDFImpl for StrposFunc {
80    fn as_any(&self) -> &dyn Any {
81        self
82    }
83
84    fn name(&self) -> &str {
85        "strpos"
86    }
87
88    fn signature(&self) -> &Signature {
89        &self.signature
90    }
91
92    fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> {
93        internal_err!("return_field_from_args should be used instead")
94    }
95
96    fn return_field_from_args(
97        &self,
98        args: datafusion_expr::ReturnFieldArgs,
99    ) -> Result<FieldRef> {
100        utf8_to_int_type(args.arg_fields[0].data_type(), "strpos/instr/position").map(
101            |data_type| {
102                Field::new(
103                    self.name(),
104                    data_type,
105                    args.arg_fields.iter().any(|x| x.is_nullable()),
106                )
107                .into()
108            },
109        )
110    }
111
112    fn invoke_with_args(
113        &self,
114        args: datafusion_expr::ScalarFunctionArgs,
115    ) -> Result<ColumnarValue> {
116        make_scalar_function(strpos, vec![])(&args.args)
117    }
118
119    fn aliases(&self) -> &[String] {
120        &self.aliases
121    }
122
123    fn documentation(&self) -> Option<&Documentation> {
124        self.doc()
125    }
126}
127
128fn strpos(args: &[ArrayRef]) -> Result<ArrayRef> {
129    match (args[0].data_type(), args[1].data_type()) {
130        (DataType::Utf8, DataType::Utf8) => {
131            let string_array = args[0].as_string::<i32>();
132            let substring_array = args[1].as_string::<i32>();
133            calculate_strpos::<_, _, Int32Type>(string_array, substring_array)
134        }
135        (DataType::Utf8, DataType::Utf8View) => {
136            let string_array = args[0].as_string::<i32>();
137            let substring_array = args[1].as_string_view();
138            calculate_strpos::<_, _, Int32Type>(string_array, substring_array)
139        }
140        (DataType::Utf8, DataType::LargeUtf8) => {
141            let string_array = args[0].as_string::<i32>();
142            let substring_array = args[1].as_string::<i64>();
143            calculate_strpos::<_, _, Int32Type>(string_array, substring_array)
144        }
145        (DataType::LargeUtf8, DataType::Utf8) => {
146            let string_array = args[0].as_string::<i64>();
147            let substring_array = args[1].as_string::<i32>();
148            calculate_strpos::<_, _, Int64Type>(string_array, substring_array)
149        }
150        (DataType::LargeUtf8, DataType::Utf8View) => {
151            let string_array = args[0].as_string::<i64>();
152            let substring_array = args[1].as_string_view();
153            calculate_strpos::<_, _, Int64Type>(string_array, substring_array)
154        }
155        (DataType::LargeUtf8, DataType::LargeUtf8) => {
156            let string_array = args[0].as_string::<i64>();
157            let substring_array = args[1].as_string::<i64>();
158            calculate_strpos::<_, _, Int64Type>(string_array, substring_array)
159        }
160        (DataType::Utf8View, DataType::Utf8View) => {
161            let string_array = args[0].as_string_view();
162            let substring_array = args[1].as_string_view();
163            calculate_strpos::<_, _, Int32Type>(string_array, substring_array)
164        }
165        (DataType::Utf8View, DataType::Utf8) => {
166            let string_array = args[0].as_string_view();
167            let substring_array = args[1].as_string::<i32>();
168            calculate_strpos::<_, _, Int32Type>(string_array, substring_array)
169        }
170        (DataType::Utf8View, DataType::LargeUtf8) => {
171            let string_array = args[0].as_string_view();
172            let substring_array = args[1].as_string::<i64>();
173            calculate_strpos::<_, _, Int32Type>(string_array, substring_array)
174        }
175
176        other => {
177            exec_err!("Unsupported data type combination {other:?} for function strpos")
178        }
179    }
180}
181
182/// Returns starting index of specified substring within string, or zero if it's not present. (Same as position(substring in string), but note the reversed argument order.)
183/// strpos('high', 'ig') = 2
184/// The implementation uses UTF-8 code points as characters
185fn calculate_strpos<'a, V1, V2, T: ArrowPrimitiveType>(
186    string_array: V1,
187    substring_array: V2,
188) -> Result<ArrayRef>
189where
190    V1: StringArrayType<'a, Item = &'a str>,
191    V2: StringArrayType<'a, Item = &'a str>,
192{
193    let ascii_only = substring_array.is_ascii() && string_array.is_ascii();
194    let string_iter = string_array.iter();
195    let substring_iter = substring_array.iter();
196
197    let result = string_iter
198        .zip(substring_iter)
199        .map(|(string, substring)| match (string, substring) {
200            (Some(string), Some(substring)) => {
201                // If only ASCII characters are present, we can use the slide window method to find
202                // the sub vector in the main vector. This is faster than string.find() method.
203                if ascii_only {
204                    // If the substring is empty, the result is 1.
205                    if substring.is_empty() {
206                        T::Native::from_usize(1)
207                    } else {
208                        T::Native::from_usize(
209                            string
210                                .as_bytes()
211                                .windows(substring.len())
212                                .position(|w| w == substring.as_bytes())
213                                .map(|x| x + 1)
214                                .unwrap_or(0),
215                        )
216                    }
217                } else {
218                    // The `find` method returns the byte index of the substring.
219                    // We count the number of chars up to that byte index.
220                    T::Native::from_usize(
221                        string
222                            .find(substring)
223                            .map(|x| string[..x].chars().count() + 1)
224                            .unwrap_or(0),
225                    )
226                }
227            }
228            _ => None,
229        })
230        .collect::<PrimitiveArray<T>>();
231
232    Ok(Arc::new(result) as ArrayRef)
233}
234
235#[cfg(test)]
236mod tests {
237    use arrow::array::{Array, Int32Array, Int64Array};
238    use arrow::datatypes::DataType::{Int32, Int64};
239
240    use arrow::datatypes::{DataType, Field};
241    use datafusion_common::{Result, ScalarValue};
242    use datafusion_expr::{ColumnarValue, ScalarUDFImpl};
243
244    use crate::unicode::strpos::StrposFunc;
245    use crate::utils::test::test_function;
246
247    macro_rules! test_strpos {
248        ($lhs:literal, $rhs:literal -> $result:literal; $t1:ident $t2:ident $t3:ident $t4:ident $t5:ident) => {
249            test_function!(
250                StrposFunc::new(),
251                vec![
252                    ColumnarValue::Scalar(ScalarValue::$t1(Some($lhs.to_owned()))),
253                    ColumnarValue::Scalar(ScalarValue::$t2(Some($rhs.to_owned()))),
254                ],
255                Ok(Some($result)),
256                $t3,
257                $t4,
258                $t5
259            )
260        };
261    }
262
263    #[test]
264    fn test_strpos_functions() {
265        // Utf8 and Utf8 combinations
266        test_strpos!("alphabet", "ph" -> 3; Utf8 Utf8 i32 Int32 Int32Array);
267        test_strpos!("alphabet", "a" -> 1; Utf8 Utf8 i32 Int32 Int32Array);
268        test_strpos!("alphabet", "z" -> 0; Utf8 Utf8 i32 Int32 Int32Array);
269        test_strpos!("alphabet", "" -> 1; Utf8 Utf8 i32 Int32 Int32Array);
270        test_strpos!("", "a" -> 0; Utf8 Utf8 i32 Int32 Int32Array);
271        test_strpos!("", "" -> 1; Utf8 Utf8 i32 Int32 Int32Array);
272        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; Utf8 Utf8 i32 Int32 Int32Array);
273
274        // LargeUtf8 and LargeUtf8 combinations
275        test_strpos!("alphabet", "ph" -> 3; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
276        test_strpos!("alphabet", "a" -> 1; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
277        test_strpos!("alphabet", "z" -> 0; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
278        test_strpos!("alphabet", "" -> 1; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
279        test_strpos!("", "a" -> 0; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
280        test_strpos!("", "" -> 1; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
281        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; LargeUtf8 LargeUtf8 i64 Int64 Int64Array);
282
283        // Utf8 and LargeUtf8 combinations
284        test_strpos!("alphabet", "ph" -> 3; Utf8 LargeUtf8 i32 Int32 Int32Array);
285        test_strpos!("alphabet", "a" -> 1; Utf8 LargeUtf8 i32 Int32 Int32Array);
286        test_strpos!("alphabet", "z" -> 0; Utf8 LargeUtf8 i32 Int32 Int32Array);
287        test_strpos!("alphabet", "" -> 1; Utf8 LargeUtf8 i32 Int32 Int32Array);
288        test_strpos!("", "a" -> 0; Utf8 LargeUtf8 i32 Int32 Int32Array);
289        test_strpos!("", "" -> 1; Utf8 LargeUtf8 i32 Int32 Int32Array);
290        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; Utf8 LargeUtf8 i32 Int32 Int32Array);
291
292        // LargeUtf8 and Utf8 combinations
293        test_strpos!("alphabet", "ph" -> 3; LargeUtf8 Utf8 i64 Int64 Int64Array);
294        test_strpos!("alphabet", "a" -> 1; LargeUtf8 Utf8 i64 Int64 Int64Array);
295        test_strpos!("alphabet", "z" -> 0; LargeUtf8 Utf8 i64 Int64 Int64Array);
296        test_strpos!("alphabet", "" -> 1; LargeUtf8 Utf8 i64 Int64 Int64Array);
297        test_strpos!("", "a" -> 0; LargeUtf8 Utf8 i64 Int64 Int64Array);
298        test_strpos!("", "" -> 1; LargeUtf8 Utf8 i64 Int64 Int64Array);
299        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; LargeUtf8 Utf8 i64 Int64 Int64Array);
300
301        // Utf8View and Utf8View combinations
302        test_strpos!("alphabet", "ph" -> 3; Utf8View Utf8View i32 Int32 Int32Array);
303        test_strpos!("alphabet", "a" -> 1; Utf8View Utf8View i32 Int32 Int32Array);
304        test_strpos!("alphabet", "z" -> 0; Utf8View Utf8View i32 Int32 Int32Array);
305        test_strpos!("alphabet", "" -> 1; Utf8View Utf8View i32 Int32 Int32Array);
306        test_strpos!("", "a" -> 0; Utf8View Utf8View i32 Int32 Int32Array);
307        test_strpos!("", "" -> 1; Utf8View Utf8View i32 Int32 Int32Array);
308        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; Utf8View Utf8View i32 Int32 Int32Array);
309
310        // Utf8View and Utf8 combinations
311        test_strpos!("alphabet", "ph" -> 3; Utf8View Utf8 i32 Int32 Int32Array);
312        test_strpos!("alphabet", "a" -> 1; Utf8View Utf8 i32 Int32 Int32Array);
313        test_strpos!("alphabet", "z" -> 0; Utf8View Utf8 i32 Int32 Int32Array);
314        test_strpos!("alphabet", "" -> 1; Utf8View Utf8 i32 Int32 Int32Array);
315        test_strpos!("", "a" -> 0; Utf8View Utf8 i32 Int32 Int32Array);
316        test_strpos!("", "" -> 1; Utf8View Utf8 i32 Int32 Int32Array);
317        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; Utf8View Utf8 i32 Int32 Int32Array);
318
319        // Utf8View and LargeUtf8 combinations
320        test_strpos!("alphabet", "ph" -> 3; Utf8View LargeUtf8 i32 Int32 Int32Array);
321        test_strpos!("alphabet", "a" -> 1; Utf8View LargeUtf8 i32 Int32 Int32Array);
322        test_strpos!("alphabet", "z" -> 0; Utf8View LargeUtf8 i32 Int32 Int32Array);
323        test_strpos!("alphabet", "" -> 1; Utf8View LargeUtf8 i32 Int32 Int32Array);
324        test_strpos!("", "a" -> 0; Utf8View LargeUtf8 i32 Int32 Int32Array);
325        test_strpos!("", "" -> 1; Utf8View LargeUtf8 i32 Int32 Int32Array);
326        test_strpos!("ДатаФусион数据融合📊🔥", "📊" -> 15; Utf8View LargeUtf8 i32 Int32 Int32Array);
327    }
328
329    #[test]
330    fn nullable_return_type() {
331        fn get_nullable(string_array_nullable: bool, substring_nullable: bool) -> bool {
332            let strpos = StrposFunc::new();
333            let args = datafusion_expr::ReturnFieldArgs {
334                arg_fields: &[
335                    Field::new("f1", DataType::Utf8, string_array_nullable).into(),
336                    Field::new("f2", DataType::Utf8, substring_nullable).into(),
337                ],
338                scalar_arguments: &[None::<&ScalarValue>, None::<&ScalarValue>],
339            };
340
341            strpos.return_field_from_args(args).unwrap().is_nullable()
342        }
343
344        assert!(!get_nullable(false, false));
345
346        // If any of the arguments is nullable, the result is nullable
347        assert!(get_nullable(true, false));
348        assert!(get_nullable(false, true));
349        assert!(get_nullable(true, true));
350    }
351}
datafusion_functions/unicode/strpos.rs

datafusion_functions/unicode/
strpos.rs
