polars_io/csv/write/
options.rs

1use std::num::NonZeroUsize;
2
3#[cfg(feature = "serde")]
4use serde::{Deserialize, Serialize};
5
6/// Options for writing CSV files.
7#[derive(Clone, Debug, Eq, Hash, PartialEq)]
8#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
9#[cfg_attr(feature = "dsl-schema", derive(schemars::JsonSchema))]
10pub struct CsvWriterOptions {
11    pub include_bom: bool,
12    pub include_header: bool,
13    pub batch_size: NonZeroUsize,
14    pub serialize_options: SerializeOptions,
15}
16
17impl Default for CsvWriterOptions {
18    fn default() -> Self {
19        Self {
20            include_bom: false,
21            include_header: true,
22            batch_size: NonZeroUsize::new(1024).unwrap(),
23            serialize_options: SerializeOptions::default(),
24        }
25    }
26}
27
28/// Options to serialize logical types to CSV.
29///
30/// The default is to format times and dates as `chrono` crate formats them.
31#[derive(Clone, Debug, Eq, Hash, PartialEq)]
32#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
33#[cfg_attr(feature = "dsl-schema", derive(schemars::JsonSchema))]
34pub struct SerializeOptions {
35    /// Used for [`DataType::Date`](polars_core::datatypes::DataType::Date).
36    pub date_format: Option<String>,
37    /// Used for [`DataType::Time`](polars_core::datatypes::DataType::Time).
38    pub time_format: Option<String>,
39    /// Used for [`DataType::Datetime`](polars_core::datatypes::DataType::Datetime).
40    pub datetime_format: Option<String>,
41    /// Used for [`DataType::Float64`](polars_core::datatypes::DataType::Float64)
42    /// and [`DataType::Float32`](polars_core::datatypes::DataType::Float32).
43    pub float_scientific: Option<bool>,
44    pub float_precision: Option<usize>,
45    /// Use comma as the decimal separator.
46    pub decimal_comma: bool,
47    /// Used as separator.
48    pub separator: u8,
49    /// Quoting character.
50    pub quote_char: u8,
51    /// Null value representation.
52    pub null: String,
53    /// String appended after every row.
54    pub line_terminator: String,
55    /// When to insert quotes.
56    pub quote_style: QuoteStyle,
57}
58
59impl Default for SerializeOptions {
60    fn default() -> Self {
61        Self {
62            date_format: None,
63            time_format: None,
64            datetime_format: None,
65            float_scientific: None,
66            float_precision: None,
67            decimal_comma: false,
68            separator: b',',
69            quote_char: b'"',
70            null: String::new(),
71            line_terminator: "\n".into(),
72            quote_style: Default::default(),
73        }
74    }
75}
76
77/// Quote style indicating when to insert quotes around a field.
78#[derive(Copy, Clone, Debug, Default, Eq, Hash, PartialEq)]
79#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
80#[cfg_attr(feature = "dsl-schema", derive(schemars::JsonSchema))]
81pub enum QuoteStyle {
82    /// Quote fields only when necessary.
83    ///
84    /// Quotes are necessary when fields contain a quote, separator or record terminator.
85    /// Quotes are also necessary when writing an empty record (which is indistinguishable
86    /// from arecord with one empty field).
87    /// This is the default.
88    #[default]
89    Necessary,
90    /// Quote every field. Always.
91    Always,
92    /// Quote non-numeric fields.
93    ///
94    /// When writing a field that does not parse as a valid float or integer,
95    /// quotes will be used even if they aren't strictly necessary.
96    NonNumeric,
97    /// Never quote any fields, even if it would produce invalid CSV data.
98    Never,
99}
polars_io/csv/write/options.rs

polars_io/csv/write/
options.rs
