我的答案是一个简短的免责声明——我只学了大约2周的Python，所以我绝不是专家；因此，我的解释可能不是最好的，我可能使用了不正确的术语。不管怎样，这就是答案。

我在代码中注意到，当您声明变量today=datetime.date.today（）时，您选择使用内置函数的名称来命名变量。

当您的下一行代码mylist.append（today）附加列表时，它附加了整个字符串datetime.date.today（），您之前将其设置为today变量的值，而不仅仅是附加today（）。

一个简单的解决方案是更改变量的名称，尽管大多数程序员在使用datetime模块时可能不会使用它。

以下是我尝试的：

import datetime
mylist = []
present = datetime.date.today()
mylist.append(present)
print present

并打印yyyy-mm-dd。

date、datetime和time对象都支持strftime（格式）方法，在显式格式的控制下创建表示时间的字符串一串

以下是格式代码及其指令和含义的列表。

%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.   
%d  Day of the month as a decimal number [01,31].    
%f  Microsecond as a decimal number [0,999999], zero-padded on the left
%H  Hour (24-hour clock) as a decimal number [00,23].    
%I  Hour (12-hour clock) as a decimal number [01,12].    
%j  Day of the year as a decimal number [001,366].   
%m  Month as a decimal number [01,12].   
%M  Minute as a decimal number [00,59].      
%p  Locale’s equivalent of either AM or PM.
%S  Second as a decimal number [00,61].
%U  Week number of the year (Sunday as the first day of the week)
%w  Weekday as a decimal number [0(Sunday),6].   
%W  Week number of the year (Monday as the first day of the week)
%x  Locale’s appropriate date representation.    
%X  Locale’s appropriate time representation.    
%y  Year without century as a decimal number [00,99].    
%Y  Year with century as a decimal number.   
%z  UTC offset in the form +HHMM or -HHMM.
%Z  Time zone name (empty string if the object is naive).    
%%  A literal '%' character.

这是我们可以使用Python中的datetime和time模块所做的

import time
import datetime

print "Time in seconds since the epoch: %s" %time.time()
print "Current date and time: ", datetime.datetime.now()
print "Or like this: ", datetime.datetime.now().strftime("%y-%m-%d-%H-%M")

print "Current year: ", datetime.date.today().strftime("%Y")
print "Month of year: ", datetime.date.today().strftime("%B")
print "Week number of the year: ", datetime.date.today().strftime("%W")
print "Weekday of the week: ", datetime.date.today().strftime("%w")
print "Day of year: ", datetime.date.today().strftime("%j")
print "Day of the month : ", datetime.date.today().strftime("%d")
print "Day of week: ", datetime.date.today().strftime("%A")

这将打印出如下内容：

Time in seconds since the epoch:    1349271346.46
Current date and time:              2012-10-03 15:35:46.461491
Or like this:                       12-10-03-15-35
Current year:                       2012
Month of year:                      October
Week number of the year:            40
Weekday of the week:                3
Day of year:                        277
Day of the month :                  03
Day of week:                        Wednesday

我讨厌为了方便而导入太多模块的想法。我宁愿使用可用的模块，在本例中是datetime，而不是调用新的模块time。

>>> a = datetime.datetime(2015, 04, 01, 11, 23, 22)
>>> a.strftime('%Y-%m-%d %H:%M')
'2015-04-01 11:23'

在Python中，可以使用datetime模块中的date、time和datetime类中的strftime（）方法格式化datetime。

在您的特定情况下，您使用的是datetime中的date类。您可以使用以下代码段将today变量格式化为格式为yyyy-MM-dd的字符串：

import datetime

today = datetime.date.today()
print("formatted datetime: %s" % today.strftime("%Y-%m-%d"))

在以下更完整的示例中：

import datetime
today = datetime.date.today()

# datetime in d/m/Y H:M:S format
date_time = today.strftime("%d/%m/%Y, %H:%M:%S")
print("datetime: %s" % date_time)

# datetime in Y-m-d H:M:S format
date_time = today.strftime("%Y-%m-%d, %H:%M:%S")
print("datetime: %s" % date_time)

# format date
date = today.strftime("%d/%m/%Y")
print("date: %s" % time)

# format time
time = today.strftime("%H:%M:%S")
print("time: %s" % time)

# day
day = today.strftime("%d")
print("day: %s" % day)

# month
month = today.strftime("%m")
print("month: %s" % month)

# year
year = today.strftime("%Y")
print("year: %s" % year)

更多指令：

来源：

在Python中设置DateTime格式斯特夫蒂姆

import datetime
import time

months = ["Unknown","January","Febuary","Marchh","April","May","June","July","August","September","October","November","December"]
datetimeWrite = (time.strftime("%d-%m-%Y "))
date = time.strftime("%d")
month= time.strftime("%m")
choices = {'01': 'Jan', '02':'Feb','03':'Mar','04':'Apr','05':'May','06': 'Jun','07':'Jul','08':'Aug','09':'Sep','10':'Oct','11':'Nov','12':'Dec'}
result = choices.get(month, 'default')
year = time.strftime("%Y")
Date = date+"-"+result+"-"+year
print Date

通过这种方式，您可以获得如下格式的日期：2017年6月22日

您需要将datetime对象转换为str。

以下代码适用于我：

import datetime

collection = []
dateTimeString = str(datetime.date.today())
collection.append(dateTimeString)
    
print(collection)

如果你需要更多帮助，请告诉我。