[](https://github.com/neilg63/fuzzy-datetime)
[](https://crates.io/crates/fuzzy-datetime)
[](https://docs.rs/fuzzy-datetime)
# Fuzzy DateTime
This library crate provides functions to detect, normalize, and complete date and datetime strings for bulk conversion to ISO 8601 compatible formats. It can fill in missing time, day, and month components if the year and other longer units are detected.
In all cases, dates must come first and may be separated from the optional time component by a space or the letter 'T'.
## Core Functions
### `fuzzy_to_datetime(dt: &str, date_opts: Option<DateOptions>, time_separator: Option<char>) -> Result<NaiveDateTime, ParseError>`
This is the most versatile function. If the last two arguments are `None`, the function will attempt to guess the format, which might lead to ambiguity between `m/d/Y` and `d/m/Y`. For processing large arrays of date-like strings, it's recommended to use format detection functions first.
```rust
let date_opts = DateOptions::dmy('/');
if let Ok(sample_chrono_datetime) = fuzzy_to_datetime("09/11/2019 17:30:45", Some(date_opts), Some(':')) {
let unix_time = sample_chrono_datetime.timestamp();
println!("Unix timestamp: {}", unix_time);
}
```
#### `fuzzy_to_datetime_string(dt: &str, date_opts: Option<DateOptions>, time_separator: Option<char>) -> Option<String>`
If you only need a normalized ISO 8601 compatible string for direct output or database storage, this function bypasses the chrono crate:
```rust
let date_opts = DateOptions::dmy('/');
if let Some(sample_chrono_datetime_string) = fuzzy_to_datetime_string("09/11/2019 17:30:45", Some(date_opts), Some(':')) {
println!("ISO 8601 string: {}", sample_chrono_datetime_string); // should be "2019-11-09T17:30:45.000Z"
} println!("{}", sample_chrono_datetime_string); // should be 2019-11-09T17:30:45.000Z
```
#### `iso_fuzzy_string_to_datetime(dt: &str) -> Result<NaiveDateTime, ParsedError>`
This assumes a *Y-m-d* date order and is fully compatible with the original function used with the [julian day- converter](https://crates.io/crates/julian_day_converter) crate.
```rust
let date_opts = DateOptions::dmy('/');
if let Ok(sample_chrono_datetime) = iso_fuzzy_string_to_datetime("2019-11-09 17") {
println!("{}", sample_chrono_datetime,to_rfc3339()); // should be 2019-11-09T17:00:45.000Z
}
```
#### `detect_date_format_from_generic_list(date_list: &[&str]) -> DateOptions` and `detect_date_format_from_generic_list<T, F>(date_list: &[T], extract_date: F) -> DateOption`
These functions identify the correct format by analyzing as many sample dates as necessary. They help determine the date format so you can apply the correct date order and separator options before converting large datasets.
In the following example, the function iterates lazily over a vector of objects, stopping at the second date which can only be interpreted as m/d/Y. The returned DateOptions can then be used with fuzzy_to_datetime() to convert all date strings in the list, skipping entries that do not match the detected format.
```rust
struct SpecialDay {
name: String,
date: String,
}
let rows: Vec<SpecialDay> = vec![
SpecialDay {
name: "Independence Day".to_string(),
date: "07/04/1776".to_string(),
},
SpecialDay {
name: "Christmas Day".to_string(),
date: "12/25/2021".to_string(),
},
SpecialDay {
name: "New Year's Day".to_string(),
date: "01/01/2022".to_string(),
},
];
let date_opts_special = detect_date_format_from_generic_list(&rows, |x| Some(x.date.clone()));
assert_eq!(date_opts_special.order(), DateOrder::MDY);
```