Rust Polars：如何显示所有列？

Question

我使用 Rust Polars，发现使用它有点困难，因为不太确定如何显示所有列。

use polars::df;

// use macro
let df = df! [
    "Column A 12345678910" => ["a", "b", "c"],
    "Column B 12345678910" => [1, 2, 3],
    "Column C 12345678910" => [Some(1), None, Some(3)],
    "Column D 12345678910" => [Some(1), None, Some(3)],
    "Column E 12345678910" => [Some(1), None, Some(3)],
    "Column F 12345678910" => [1, 2, 3],
    "Column G 12345678910" => [1, 2, 3],
    "Column Z 12345678910" => [1, 2, 3],
    "Column Ex 12345678910" => [Some(1), None, Some(3)],
    "Column Fs 12345678910" => [1, 2, 3],
    "Column Ga 12345678910" => [1, 2, 3],
    "Column Zz 12345678910" => [1, 2, 3],
]?;
println!("{:?}", df);

输出

shape: (3, 12)
+----------------------+----------------------+----------------------+----------------------+-----+-----------------------+-----------------------+-----------------------+-----------------------+
| Column A 12345678910 | Column B 12345678910 | Column C 12345678910 | Column D 12345678910 | ... | Column Ex 12345678910 | Column Fs 12345678910 | Column Ga 12345678910 | Column Zz 12345678910 |
| ---                  | ---                  | ---                  | ---                  |     | ---                   | ---                   | ---                   | ---                   |
| str                  | i32                  | i32                  | i32                  |     | i32                   | i32                   | i32                   | i32                   |
+======================+======================+======================+======================+=====+=======================+=======================+=======================+=======================+
| a                    | 1                    | 1                    | 1                    | ... | 1                     | 1                     | 1                     | 1                     |
+----------------------+----------------------+----------------------+----------------------+-----+-----------------------+-----------------------+-----------------------+-----------------------+
| b                    | 2                    | null                 | null                 | ... | null                  | 2                     | 2                     | 2                     |
+----------------------+----------------------+----------------------+----------------------+-----+-----------------------+-----------------------+-----------------------+-----------------------+
| c                    | 3                    | 3                    | 3                    | ... | 3                     | 3                     | 3                     | 3                     |
+----------------------+----------------------+----------------------+----------------------+-----+-----------------------+-----------------------+-----------------------+-----------------------+

是否可以显示所有带有生锈极坐标的列？

Answer 1

您可以通过将

POLARS_FMT_MAX_COLS

设置为您想要的最大列数来更改默认值。

在文档中查看更多环境变量设置：https://pola-rs.github.io/polars/polars/index.html#config-with-env-vars

Answer 2

我特别喜欢使用圆角。
例如，我使用这个配置环境：

use polars::prelude::*;
use std::{
    env,
    error::Error,
};

fn main() -> Result<(), Box<dyn Error>> {

    // set MAX_COLS to 20
    configure_the_environment();

    // df with 12 columns
    let dataframe = df! [
        "Column A 12345678910" => ["a", "b", "c"],
        "Column B 12345678910" => [1, 2, 3],
        "Column C 12345678910" => [Some(1), None, Some(3)],
        "Column D 12345678910" => [Some(1), None, Some(3)],
        "Column E 12345678910" => [Some(1), None, Some(3)],
        "Column F 12345678910" => [1, 2, 3],
        "Column G 12345678910" => [1, 2, 3],
        "Column Z 12345678910" => [1, 2, 3],
        "Column Ex 12345678910" => [Some(1), None, Some(3)],
        "Column Fs 12345678910" => [1, 2, 3],
        "Column Ga 12345678910" => [1, 2, 3],
        "Column Zz 12345678910" => [1, 2, 3],
    ]?;

    println!("{:?}", dataframe);

    Ok(())
}

/// Configure Polars with ENV vars
pub fn configure_the_environment() {
    env::set_var("POLARS_FMT_TABLE_ROUNDED_CORNERS", "1"); // apply rounded corners to UTF8-styled tables.
    env::set_var("POLARS_FMT_MAX_COLS", "20"); // maximum number of columns shown when formatting DataFrames.
    env::set_var("POLARS_FMT_MAX_ROWS", "10"); // maximum number of rows shown when formatting DataFrames.
    env::set_var("POLARS_FMT_STR_LEN", "50");  // maximum number of characters printed per string value.
}

输出：

shape: (3, 12)
╭─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬─────────────┬────────────────────────┬───────────────────────┬───────────────────────┬───────────────────────╮
│ Column A    ┆ Column B    ┆ Column C    ┆ Column D    ┆ Column E    ┆ Column F    ┆ Column G    ┆ Column Z    ┆ Column Ex 12345678910  ┆ Column Fs 12345678910 ┆ Column Ga 12345678910 ┆ Column Zz 12345678910 │
│ 12345678910 ┆ 12345678910 ┆ 12345678910 ┆ 12345678910 ┆ 12345678910 ┆ 12345678910 ┆ 12345678910 ┆ 12345678910 ┆ ---                    ┆ ---                   ┆ ---                   ┆ ---                   │
│ ---         ┆ ---         ┆ ---         ┆ ---         ┆ ---         ┆ ---         ┆ ---         ┆ ---         ┆ i32                    ┆ i32                   ┆ i32                   ┆ i32                   │
│ str         ┆ i32         ┆ i32         ┆ i32         ┆ i32         ┆ i32         ┆ i32         ┆ i32         ┆                        ┆                       ┆                       ┆                       │
╞═════════════╪═════════════╪═════════════╪═════════════╪═════════════╪═════════════╪═════════════╪═════════════╪════════════════════════╪═══════════════════════╪═══════════════════════╪═══════════════════════╡
│ a           ┆ 1           ┆ 1           ┆ 1           ┆ 1           ┆ 1           ┆ 1           ┆ 1           ┆ 1                      ┆ 1                     ┆ 1                     ┆ 1                     │
│ b           ┆ 2           ┆ null        ┆ null        ┆ null        ┆ 2           ┆ 2           ┆ 2           ┆ null                   ┆ 2                     ┆ 2                     ┆ 2                     │
│ c           ┆ 3           ┆ 3           ┆ 3           ┆ 3           ┆ 3           ┆ 3           ┆ 3           ┆ 3                      ┆ 3                     ┆ 3                     ┆ 3                     │
╰─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴─────────────┴────────────────────────┴───────────────────────┴───────────────────────┴───────────────────────╯