遍历日期范围 [英] Loop over date range

问题描述

在Python3中，我可以像这样遍历一系列日期

In Python3, I can loop over a range of dates like this

import datetime

dt0 = datetime.datetime(2017, 1, 1, 0, 0, 0)
dt1 = datetime.datetime(2017, 1, 5, 0, 0, 0)
dt = dt0
while dt <= dt1:
    print(dt.strftime("%Y-%m-%d %H:%M:%S"))
    dt += datetime.timedelta(days=1)

在Rust中是否有类似的方法来循环日期? 我知道我可以在几个月中然后在一个月中的几天内编写一个嵌套循环.像这样:

Is there a similar way to loop over dates in Rust? I know that I could write a nested loop over the months then the days of the month. Like this:

let days = [1, 2, 3, 4, 5, 6, 7,
            8, 9, 10, 11, 12, 13, 14, 
            15, 16, 17, 18, 19, 20, 21,
            22, 23, 24, 25, 26, 27, 28, 29, 30, 31];
let months = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12];
let months_30_days = [4, 6, 9, 11];

for month in months.iter() {
    for day in days.iter() {
        if month == &2 {
            if is_leap_year(year) {
                if day > &29 {
                    continue;
                }
            } else if day > &28 {
                continue;
            }
        } else if months_30_days.contains(&month) && day > &30 {
            continue;
        }

        print!("{:04}-{:02}-{:02} ", year, month, day);
    }
}

fn is_leap_year(year: i32) -> bool {
    if year % 100 == 0 {
        return year % 400 == 0;
    } else {
        return year % 4 == 0;
    }
}

还有更乡村的方式吗?

推荐答案

您可以使用 chrono 放在箱子里

You could use the chrono crate for that:

extern crate chrono; // 0.4.6

use chrono::{Duration, TimeZone, Utc};

fn main() {
    let dt0 = Utc.ymd(2017, 1, 1);
    let dt1 = Utc.ymd(2017, 1, 5);

    let mut dt = dt0;
    while dt <= dt1 {
        println!("{:?}", dt);
        dt = dt + Duration::days(1);
    }
}

这也可以包装到迭代器中:

This can also be wrapped into an iterator:

extern crate chrono; // 0.4.6

use chrono::{Date, Duration, TimeZone, Utc};
use std::mem;

struct DateRange(Date<Utc>, Date<Utc>);

impl Iterator for DateRange {
    type Item = Date<Utc>;
    fn next(&mut self) -> Option<Self::Item> {
        if self.0 <= self.1 {
            let next = self.0 + Duration::days(1);
            Some(mem::replace(&mut self.0, next))
        } else {
            None
        }
    }
}

fn main() {
    let dt0 = Utc.ymd(2017, 1, 1);
    let dt1 = Utc.ymd(2017, 1, 5);

    for dt in DateRange(dt0, dt1) {
        println!("{:?}", dt);
    }
}

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