在Python中使用list和if语句将字符串（用户输入）转换为整数

Question

最近我有一个学校的项目，在这个项目中，我需要把一个用户输入作为1-12（代表一年中的月份）和用户年龄之间的整数，然后做一个数学等式来产生一个数字，这个数字将吐出用户的年龄和出生月份（是的，我知道这是多余的，但我必须做数学等式，而不是吐出用户的输入）。我是一个想要100%输入的孩子，他试图让用户通过字符串输入月份，例如（Jan=1）使用列表和if语句。如果语句不改变birthNum变量，那么下面的代码就不会像用户输入东西时那样工作。所以请帮帮我，因为我几乎什么都试过了，什么都不管用，但我觉得好像我就快成功了。你知道吗

下面是将用户输入（字符串）转换为整数的代码：

birthNum = 0

listOfMonths = ["January", "Jan", "january", "jan", "1", "Febuary", "Feb", "febuary", "feb", "2", "March", "Mar", "march", "mar", "3", "April", "Apr", "april", "apr", "4", "May", "may", "5", "June", "Jun", "june", "jun", "6", "July", "Jul", "july", "jul", "7", "August", "Aug", "august", "aug", "8", "September", "Sept", "september", "sept", "9", "October", "Oct", "october", "oct", "10", "November", "Nov", "november", "nov", "11", "December", "Dec", "december", "dec", "12"]

janList = ["January", "Jan", "january", "jan", "1"]

febList = ["Febuary", "Feb", "febuary", "feb", "2"]

marList = ["March", "Mar", "march", "mar", "3"]

aprList = ["April", "Apr", "april", "apr", "4"]

mayList = ["May", "may", "5"]

junList = ["June", "Jun", "june", "jun", "6"]

julList = ["Jul", "july", "jul", "7"]

augList = ["September", "Sept", "september", "sept", "9"]

septList = ["September", "Sept", "september", "sept", "9"]

octList = ["October", "Oct", "october", "oct", "10"]

novList = ["November", "Nov", "november", "nov", "11"]

decList = ["December", "Dec", "december", "dec", "12"]

(birthMonthInput) = input("Please put in your birth month: ")


if (birthMonthInput == (janList)):
    birthNum = int(1)

if (birthMonthInput == (febList)):
    birthNum = int(2)

if (birthMonthInput == (marList)):
    birthNum = int(3)

if (birthMonthInput == (aprList)):
    birthNum = int(4)

if (birthMonthInput == (mayList)):
    birthNum = int(5)

if (birthMonthInput == (junList)):
    birthNum = int(6)

if (birthMonthInput == (julList)):
    birthNum = int(7)

if (birthMonthInput == (augList)):
    birthNum = int(8)

if (birthMonthInput == (septList)):
    birthNum = int(9)

if (birthMonthInput == (octList)):
    birthNum = int(10)

if (birthMonthInput == (novList)):
    birthNum = int(11)

if (birthMonthInput == (decList)):
    birthNum = int(12)

print (birthNum)

Answer 1

为此使用列表是非常不好的。您的解决方案需要大约5*12次查找才能获得与字符串关联的值。你知道吗

可以在O(1)中完成这个用例的一种更快的数据结构是dict。 尝试将代码格式化为以下格式：

dic = {
   "Jan": 1,
   "January": 1,
   "Feb": 2 # and so on
}

然后，您只需执行以下操作即可获得解决方案：

birthNum = dict[birthMonthInput]

阅读python data structures了解一个好的概述。词典见第5.5节