Цикл для ввода даты

#python #python_3x #datetime

Подскажите, пожалуйста, как правильно написать цикл для ввода даты, чтобы он предлагал
ввести значение из диапазона до тех пор, пока не будет введено это значение правильно. 

import random
from datetime import datetime

start_date = datetime.strptime("01.01.2016", "%d.%m.%Y")
end_date = datetime.strptime("01.01.2019", "%d.%m.%Y")
x = random.randint(-30, 30)
while True:
     prompt = "Input a date from the range [{:%d.%m.%Y} - {:%d.%m.%Y}]: ".format(start_date,
end_date)
     try:
         user_date = datetime.strptime(input(prompt), "%d.%m.%Y")
         if start_date <= user_date <= end_date:
             break
         if user_date >= end_date or user_date <= start_date:
             print("Please, select date from 01.01.2016 to 01.01.2019")
     except ValueError:
         print("Please enter a correct date")
print(f'User_date: {user_date:%d.%m.%Y}')
print("What a forecast do you want to see?")
print("1)Weather today")
print("2)Weather in 3 days")
print("3)Weather in 5 days")
print("4)Weather in 7 days")
while True:
    a1 = int(input("Weather:\n>"))
    try:
        if a1 == 1:
            if (start_date <= user_date <= end_date):
                print(x)
                break
        if a1 == 2:
            if (start_date <= user_date <= end_date):
                print(x * 3)
                break
        if a1 == 3:
            if (start_date <= user_date <= end_date):
                print(x * 5)
                break
        if a1 == 4:
            if (start_date <= user_date <= end_date):
                print(x * 7)
                break
        if a1 < 1 or a1 > 4:
            print("Please, select position from 1 to 4!")
            break
    except ValueError:
        print("Please enter a correct number")

    

Ответы

Ответ 1

UPDATE:

def inp_dt_from_range(start_date, end_date):
    while True:
        prompt = "Input a date from the range [{:%d.%m.%Y} - {:%d.%m.%Y}]: " \
                 .format(start_date, end_date)

        try:
            user_date = datetime.strptime(input(prompt), "%d.%m.%Y")
            if start_date <= user_date <= end_date:
                break
        except ValueError:
            pass
    return user_date

def choose_int_option(text, prompt, options=[1,2,3]):
    print(text)
    while True:
        try:
            ret = int(input(prompt))
            if ret in options:
                return ret
        except ValueError:
            pass


text = """
What a forecast do you want to see?
1) Weather today
2) Weather in 3 days
3) Weather in 5 days
4) Weather in 7 days"""

user_date = inp_dt_from_range(start_date, end_date)
opt_range = list(range(1,5))
prompt = f'Input an integer from within a range: {opt_range}: '
opt = choose_int_option(text, prompt, opt_range)


Пример:

In [7]: user_date = inp_dt_from_range(start_date, end_date)
   ...: opt_range = list(range(1,5))
   ...: prompt = f'Input an integer from within a range: {opt_range}: '
   ...: opt = choose_int_option(text, prompt, opt_range)
Input a date from the range [01.01.2016 - 01.01.2019]: asasa
Input a date from the range [01.01.2016 - 01.01.2019]: 11.11.2018

What a forecast do you want to see?
1) Weather today
2) Weather in 3 days
3) Weather in 5 days
4) Weather in 7 days
Input an integer from within a range: [1, 2, 3, 4]: qwq
Input an integer from within a range: [1, 2, 3, 4]: 0
Input an integer from within a range: [1, 2, 3, 4]: 2

In [8]: print(f'user_date: {user_date:%d.%m.%Y}\topt: {opt}')
user_date: 11.11.2018   opt: 2




Ответ на вопрос до редактирования:

In [9]: while True:
   ...:     prompt = "Input a date from the range [{:%d.%m.%Y} - {:%d.%m.%Y}]: " \
   ...:              .format(start_date, end_date)
   ...:
   ...:     try:
   ...:         user_date = datetime.strptime(input(prompt), "%d.%m.%Y")
   ...:         if start_date <= user_date <= end_date:
   ...:             break
   ...:     except ValueError:
   ...:         pass
   ...:
   ...: print(f'user_date: {user_date:%d.%m.%Y}')


Вывод:

Input a date from the range [01.01.2016 - 01.01.2019]: ababa
Input a date from the range [01.01.2016 - 01.01.2019]: 01.15.2018
Input a date from the range [01.01.2016 - 01.01.2019]: 31.12.2018
user_date: 31.12.2018


Ответ 2

import datetime

start_date = datetime.datetime.strptime("01.01.2016", "%d.%m.%Y")
end_date = datetime.datetime.strptime("01.01.2019", "%d.%m.%Y")

user_date = datetime.datetime.strptime("01.01.2010", "%d.%m.%Y")    # вне диапазона

while not start_date < user_date < end_date:   # или <= (как вам надо)
    user_date = datetime.datetime.strptime(input("Choose date: \n"), "%d.%m.%Y")