【python】Human readable duration format 時(shí)間格式轉(zhuǎn)換

liangzai_cool 發(fā)布于2019-07-25 10:44 / 2930人閱讀

摘要：背景上的一道原題，通過格式劃字符串精簡了代碼結(jié)構(gòu)，省去了很多條件判斷語句。題目描述解題思路題目是很簡單的，關(guān)鍵是如何優(yōu)雅地完成是否在當(dāng)前時(shí)間單位后添加和或者，我的代碼里運(yùn)用了很多語句。代碼感想表達(dá)式真是一個(gè)神器。

背景

CodeWar上的一道原題，通過格式劃字符串精簡了代碼結(jié)構(gòu)，省去了很多條件判斷語句。

題目描述

Your task in order to complete this Kata is to write a function which formats a duration, given as a number of seconds, in a human-friendly way.

The function must accept a non-negative integer. If it is zero, it just returns "now". Otherwise, the duration is expressed as a combination of years, days, hours, minutes and seconds.

It is much easier to understand with an example:

format_duration(62)    # returns "1 minute and 2 seconds"
  format_duration(3662)  # returns "1 hour, 1 minute and 2 seconds"

Note that spaces are important.

Detailed rules

The resulting expression is made of components like 4 seconds, 1 year, etc. In general, a positive integer and one of the valid units of time, separated by a space. The unit of time is used in plural if the integer is greater than 1.

The components are separated by a comma and a space (", "). Except the last component, which is separated by " and ", just like it would be written in English.

A more significant units of time will occur before than a least significant one. Therefore, 1 second and 1 year is not correct, but 1 year and 1 second is.

Different components have different unit of times. So there is not repeated units like in 5 seconds and 1 second.

A component will not appear at all if its value happens to be zero. Hence, 1 minute and 0 seconds is not valid, but it should be just 1 minute.

A unit of time must be used "as much as possible". It means that the function should not return 61 seconds, but 1 minute and 1 second instead. Formally, the duration specified by of a component must not be greater than any valid more significant unit of time.

For the purpose of this Kata, a year is 365 days and a day is 24 hours.

解題思路

題目是很簡單的，關(guān)鍵是如何優(yōu)雅地完成是否在當(dāng)前時(shí)間單位后添加"s"和","或者"and"，我的代碼里運(yùn)用了很多

true_value if condition else false_value

語句。

代碼

def format_duration(seconds):
    if seconds == 0: return "now"
    origin = seconds
    dic = {
        "year": 60 * 60 * 24 * 365,
        "day": 60 * 60 * 24,
        "hour": 60 * 60,
        "minute": 60,
        "second": 1
    }
    spent = {}
    ans = ""
    for x in ["year","day","hour","minute","second"]:
        spent[x] = seconds // dic[x]
        ans += "{}{} {}{}".format("" if seconds == origin else " and " if seconds % dic[x] == 0 else ", ",spent[x],x,"s" if spent[x] > 1 else "") if spent[x] > 0 else ""
        seconds %= dic[x]
    return  ans

感想

if else 表達(dá)式真是一個(gè)神器。