polars_plan/dsl/functions/
syntactic_sugar.rs

1use polars_core::chunked_array::cast::CastOptions;
2
3use super::*;
4
5/// Sum all the values in the column named `name`. Shorthand for `col(name).sum()`.
6pub fn sum(name: &str) -> Expr {
7    col(name).sum()
8}
9
10/// Find the minimum of all the values in the column named `name`. Shorthand for `col(name).min()`.
11pub fn min(name: &str) -> Expr {
12    col(name).min()
13}
14
15/// Find the maximum of all the values in the column named `name`. Shorthand for `col(name).max()`.
16pub fn max(name: &str) -> Expr {
17    col(name).max()
18}
19
20/// Find the mean of all the values in the column named `name`. Shorthand for `col(name).mean()`.
21pub fn mean(name: &str) -> Expr {
22    col(name).mean()
23}
24
25/// Find the mean of all the values in the column named `name`. Alias for [`mean`].
26pub fn avg(name: &str) -> Expr {
27    col(name).mean()
28}
29
30/// Find the median of all the values in the column named `name`. Shorthand for `col(name).median()`.
31pub fn median(name: &str) -> Expr {
32    col(name).median()
33}
34
35/// Find a specific quantile of all the values in the column named `name`.
36pub fn quantile(name: &str, quantile: Expr, method: QuantileMethod) -> Expr {
37    col(name).quantile(quantile, method)
38}
39
40/// Negates a boolean column.
41pub fn not(expr: Expr) -> Expr {
42    expr.not()
43}
44
45/// A column which is `true` wherever `expr` is null, `false` elsewhere.
46pub fn is_null(expr: Expr) -> Expr {
47    expr.is_null()
48}
49
50/// A column which is `false` wherever `expr` is null, `true` elsewhere.
51pub fn is_not_null(expr: Expr) -> Expr {
52    expr.is_not_null()
53}
54
55/// Casts the column given by `Expr` to a different type.
56///
57/// Follows the rules of Rust casting, with the exception that integers and floats can be cast to `DataType::Date` and
58/// `DataType::DateTime(_, _)`. A column consisting entirely of `Null` can be cast to any type, regardless of the
59/// nominal type of the column.
60pub fn cast(expr: Expr, dtype: DataType) -> Expr {
61    Expr::Cast {
62        expr: Arc::new(expr),
63        dtype,
64        options: CastOptions::NonStrict,
65    }
66}
polars_plan/dsl/functions/syntactic_sugar.rs

polars_plan/dsl/functions/
syntactic_sugar.rs
