我不明白日期时间

问题描述：

我试图使用datetime模块和我永远不能得到它的此代码工作：我不明白日期时间

class Loan: 
    def __init__(self, person_name, bookLoaned, loanStart, loanEnd): 
     self.personName = person_name 
     self.bookLoaned = bookLoaned 
     self.loanStart = datetime.date(loanStart) 
     self.loanEnd = datetime.date(loanEnd)

出于某种原因，PyScripter被给了一个错误“类型错误：一个整数是必需的（获得类型str）“。

我拆款这样的： loan1 =贷款（borrower1.name，BookCopy1.title，（ “22/06/2016”），（ “22/06/2018”））

我期待它是某种语法错误（这就是为什么我认为只需要发布该方法而不是整个脚本）有人可以帮忙吗？

你怎么叫'Loan'与 – user1767754

开始什么错误？请阅读如何发布[mcve]并适当编辑您的问题。你读过'datetime.date'的文档吗？它需要三个参数。 –

答

让我们来看看：

>>> import datetime 
>>> help(datetime.date) 
Help on class date in module datetime: 

class date(builtins.object) 
| date(year, month, day) --> date object 
: 
>>> datetime.date(2016,6,22) 
datetime.date(2016, 6, 22)

date并不需要一个字符串。纵观help(datetime)，strptime听起来像你想要什么：

>>> help(datetime.datetime.strptime) 
Help on built-in function strptime: 

strptime(...) method of builtins.type instance 
    string, format -> new datetime parsed from a string (like time.strptime()).

此功能需要像你想要一个字符串，也是一种格式。让我们来看看time.strptime不得不说的格式：

>>> import time 
>>> help(time.strptime) 
Help on built-in function strptime in module time: 

strptime(...) 
    strptime(string, format) -> struct_time 

    Parse a string to a time tuple according to a format specification. 
    See the library reference manual for formatting codes (same as 
    strftime()). 

    Commonly used format codes: 

    %Y Year with century as a decimal number. 
    %m Month as a decimal number [01,12]. 
    %d Day of the month as a decimal number [01,31]. 
    %H Hour (24-hour clock) as a decimal number [00,23]. 
    %M Minute as a decimal number [00,59]. 
    %S Second as a decimal number [00,61]. 
    %z Time zone offset from UTC. 
    %a Locale's abbreviated weekday name. 
    %A Locale's full weekday name. 
    %b Locale's abbreviated month name. 
    %B Locale's full month name. 
    %c Locale's appropriate date and time representation. 
    %I Hour (12-hour clock) as a decimal number [01,12]. 
    %p Locale's equivalent of either AM or PM. 

    Other codes may be available on your platform. See documentation for 
    the C library strftime function.

所以一个datetime对象可以从一个字符串和一个合适的格式创建：

>>> datetime.datetime.strptime('22/06/2016','%d/%m/%Y') 
datetime.datetime(2016, 6, 22, 0, 0)

，但你只想要一个date。回首帮助datetime.datetime，它有一个date()方法：

>>> datetime.datetime.strptime('22/06/2016','%d/%m/%Y').date() 
datetime.date(2016, 6, 22)

为您的代码（作为MCVE）：

import datetime 

def date_from_string(strdate): 
    return datetime.datetime.strptime(strdate,'%d/%m/%Y').date() 

class Loan: 
    def __init__(self, person_name, bookLoaned, loanStart, loanEnd): 
     self.personName = person_name 
     self.bookLoaned = bookLoaned 
     self.loanStart = date_from_string(loanStart) 
     self.loanEnd = date_from_string(loanEnd) 

loan1 = Loan('John doe', 'Book Title', "22/06/2016", "22/06/2018")

我不明白日期时间

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