polars_plan/dsl/functions/
concat.rs

1use super::*;
2
3#[cfg(all(feature = "concat_str", feature = "strings"))]
4/// Horizontally concat string columns in linear time
5pub fn concat_str<E: AsRef<[Expr]>>(s: E, separator: &str, ignore_nulls: bool) -> Expr {
6    let input = s.as_ref().to_vec();
7    let separator = separator.into();
8
9    Expr::Function {
10        input,
11        function: StringFunction::ConcatHorizontal {
12            delimiter: separator,
13            ignore_nulls,
14        }
15        .into(),
16        options: FunctionOptions {
17            collect_groups: ApplyOptions::ElementWise,
18            flags: FunctionFlags::default()
19                | FunctionFlags::INPUT_WILDCARD_EXPANSION & !FunctionFlags::RETURNS_SCALAR,
20            ..Default::default()
21        },
22    }
23}
24
25#[cfg(all(feature = "concat_str", feature = "strings"))]
26/// Format the results of an array of expressions using a format string
27pub fn format_str<E: AsRef<[Expr]>>(format: &str, args: E) -> PolarsResult<Expr> {
28    let mut args: std::collections::VecDeque<Expr> = args.as_ref().to_vec().into();
29
30    // Parse the format string, and separate substrings between placeholders
31    let segments: Vec<&str> = format.split("{}").collect();
32
33    polars_ensure!(
34        segments.len() - 1 == args.len(),
35        ShapeMismatch: "number of placeholders should equal the number of arguments"
36    );
37
38    let mut exprs: Vec<Expr> = Vec::new();
39
40    for (i, s) in segments.iter().enumerate() {
41        if i > 0 {
42            if let Some(arg) = args.pop_front() {
43                exprs.push(arg);
44            }
45        }
46
47        if !s.is_empty() {
48            exprs.push(lit(s.to_string()))
49        }
50    }
51
52    Ok(concat_str(exprs, "", false))
53}
54
55/// Concat lists entries.
56pub fn concat_list<E: AsRef<[IE]>, IE: Into<Expr> + Clone>(s: E) -> PolarsResult<Expr> {
57    let s: Vec<_> = s.as_ref().iter().map(|e| e.clone().into()).collect();
58
59    polars_ensure!(!s.is_empty(), ComputeError: "`concat_list` needs one or more expressions");
60
61    Ok(Expr::Function {
62        input: s,
63        function: FunctionExpr::ListExpr(ListFunction::Concat),
64        options: FunctionOptions {
65            collect_groups: ApplyOptions::ElementWise,
66            flags: FunctionFlags::default() | FunctionFlags::INPUT_WILDCARD_EXPANSION,
67            ..Default::default()
68        },
69    })
70}
71
72/// Horizontally concatenate columns into a single array-type column.
73pub fn concat_arr(input: Vec<Expr>) -> PolarsResult<Expr> {
74    feature_gated!("dtype-array", {
75        polars_ensure!(!input.is_empty(), ComputeError: "`concat_arr` needs one or more expressions");
76
77        Ok(Expr::Function {
78            input,
79            function: FunctionExpr::ArrayExpr(ArrayFunction::Concat),
80            options: FunctionOptions {
81                collect_groups: ApplyOptions::ElementWise,
82                flags: FunctionFlags::default() | FunctionFlags::INPUT_WILDCARD_EXPANSION,
83                ..Default::default()
84            },
85        })
86    })
87}
88
89pub fn concat_expr<E: AsRef<[IE]>, IE: Into<Expr> + Clone>(
90    s: E,
91    rechunk: bool,
92) -> PolarsResult<Expr> {
93    let s: Vec<_> = s.as_ref().iter().map(|e| e.clone().into()).collect();
94    polars_ensure!(!s.is_empty(), ComputeError: "`concat_expr` needs one or more expressions");
95
96    Ok(Expr::Function {
97        input: s,
98        function: FunctionExpr::ConcatExpr(rechunk),
99        options: FunctionOptions {
100            collect_groups: ApplyOptions::ElementWise,
101            flags: FunctionFlags::default() | FunctionFlags::INPUT_WILDCARD_EXPANSION,
102            cast_options: Some(CastingRules::cast_to_supertypes()),
103            ..Default::default()
104        },
105    })
106}
polars_plan/dsl/functions/concat.rs

polars_plan/dsl/functions/
concat.rs
