python - 不使用 if else 的货币转换器

Question

我正在使用 tkinter 上的 if-else 语句编写货币转换器程序。我只为其中六种货币编写了它，而且花费的时间太长。

如果我想为数百种货币写作怎么办？我也使用 if-else 吗？有没有更有效的方法来编程货币转换器而不使用 If-Else 语句？

from tkinter import ttk
from tkinter import *
import tkinter as tk


class CurrencyConverter(tk.Tk):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.title('Currency Converter')
        self.geometry('500x300')

        self.currencies_list = ['United States Dollar', 'Pound Sterling', 'Euro', 'Pakistani Rupee', 'Swiss Franc',
                                'Japanese Yen']
        self.usd_to_other_list = [1, 0.72, 0.85, 153.50, 0.94, 110.70]
        self.ps_to_other_list = [1.38, 1, 1.18, 212.15, 1.3, 153]
        self.euro_to_other_list = [1.18, 0.85, 1, 180.55, 1.11, 130.19]
        self.pkr_to_other_list = [0.0065, 0.0047, 0.0055, 1, 0.0061, 0.72]
        self.sf_to_other_list = [1.06, 0.77, 0.9, 162.79, 1, 117.46]
        self.jy_to_other_list = [0.009, 0.0065, 0.0077, 1.39, 0.0085, 1]

        self.from_currency = tk.StringVar()
        self.to_currency = tk.StringVar()
        self.from_entry_variable = tk.IntVar()
        self.to_entry_variable = tk.IntVar()

        self.from_entry = ttk.Entry(
            self,
            textvariable=self.from_entry_variable,
            width=40
        )
        self.from_combobox = ttk.Combobox(
            self,
            textvariable=self.from_currency,
            values=tuple(self.currencies_list),
            state='readonly'
        )
        self.from_combobox.set(self.currencies_list[0])

        self.to_entry = ttk.Entry(
            self,
            textvariable=self.to_entry_variable,
            width=40,
            state='readonly'
        )
        self.to_combobox = ttk.Combobox(
            self,
            textvariable=self.to_currency,
            values=tuple(self.currencies_list),
            state='readonly'
        )
        self.to_combobox.set(self.currencies_list[4])

        self.from_entry.pack()
        self.from_combobox.pack()
        self.to_entry.pack()
        self.to_combobox.pack()

        self.from_entry.bind('<KeyPress>', self.currency_converter)
        self.from_entry.bind('<KeyRelease>', self.currency_converter)

    def currency_converter(self, event):
        try:
            if self.from_currency.get() == 'United States Dollar':

                if self.to_currency.get() == 'United States Dollar':
                    converted = int(self.from_entry_variable.get()) * self.usd_to_other_list[0]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pound Sterling':
                    converted = int(self.from_entry_variable.get()) * self.usd_to_other_list[1]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Euro':
                    converted = int(self.from_entry_variable.get()) * self.usd_to_other_list[2]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pakistani Rupee':
                    converted = int(self.from_entry_variable.get()) * self.usd_to_other_list[3]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Swiss Franc':
                    converted = int(self.from_entry_variable.get()) * self.usd_to_other_list[4]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Japanese Yen':
                    converted = int(self.from_entry_variable.get()) * self.usd_to_other_list[5]
                    self.to_entry_variable.set(value=f'{converted}')

            elif self.from_currency.get() == 'Pound Sterling':

                if self.to_currency.get() == 'United States Dollar':
                    converted = int(self.from_entry_variable.get()) * self.ps_to_other_list[0]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pound Sterling':
                    converted = int(self.from_entry_variable.get()) * self.ps_to_other_list[1]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Euro':
                    converted = int(self.from_entry_variable.get()) * self.ps_to_other_list[2]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pakistani Rupee':
                    converted = int(self.from_entry_variable.get()) * self.ps_to_other_list[3]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Swiss Franc':
                    converted = int(self.from_entry_variable.get()) * self.ps_to_other_list[4]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Japanese Yen':
                    converted = int(self.from_entry_variable.get()) * self.ps_to_other_list[5]
                    self.to_entry_variable.set(value=f'{converted}')

            elif self.from_currency.get() == 'Euro':

                if self.to_currency.get() == 'United States Dollar':
                    converted = int(self.from_entry_variable.get()) * self.euro_to_other_list[0]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pound Sterling':
                    converted = int(self.from_entry_variable.get()) * self.euro_to_other_list[1]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Euro':
                    converted = int(self.from_entry_variable.get()) * self.euro_to_other_list[2]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pakistani Rupee':
                    converted = int(self.from_entry_variable.get()) * self.euro_to_other_list[3]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Swiss Franc':
                    converted = int(self.from_entry_variable.get()) * self.euro_to_other_list[4]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Japanese Yen':
                    converted = int(self.from_entry_variable.get()) * self.euro_to_other_list[5]
                    self.to_entry_variable.set(value=f'{converted}')

            elif self.from_currency.get() == 'Pakistani Rupee':

                if self.to_currency.get() == 'United States Dollar':
                    converted = int(self.from_entry_variable.get()) * self.pkr_to_other_list[0]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pound Sterling':
                    converted = int(self.from_entry_variable.get()) * self.pkr_to_other_list[1]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Euro':
                    converted = int(self.from_entry_variable.get()) * self.pkr_to_other_list[2]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pakistani Rupee':
                    converted = int(self.from_entry_variable.get()) * self.pkr_to_other_list[3]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Swiss Franc':
                    converted = int(self.from_entry_variable.get()) * self.pkr_to_other_list[4]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Japanese Yen':
                    converted = int(self.from_entry_variable.get()) * self.pkr_to_other_list[5]
                    self.to_entry_variable.set(value=f'{converted}')

            elif self.from_currency.get() == 'Swiss Franc':

                if self.to_currency.get() == 'United States Dollar':
                    converted = int(self.from_entry_variable.get()) * self.sf_to_other_list[0]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pound Sterling':
                    converted = int(self.from_entry_variable.get()) * self.sf_to_other_list[1]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Euro':
                    converted = int(self.from_entry_variable.get()) * self.sf_to_other_list[2]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pakistani Rupee':
                    converted = int(self.from_entry_variable.get()) * self.sf_to_other_list[3]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Swiss Franc':
                    converted = int(self.from_entry_variable.get()) * self.sf_to_other_list[4]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Japanese Yen':
                    converted = int(self.from_entry_variable.get()) * self.sf_to_other_list[5]
                    self.to_entry_variable.set(value=f'{converted}')

            elif self.from_currency.get() == 'Japanese Yen':

                if self.to_currency.get() == 'United States Dollar':
                    converted = int(self.from_entry_variable.get()) * self.jy_to_other_list[0]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pound Sterling':
                    converted = int(self.from_entry_variable.get()) * self.jy_to_other_list[1]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Euro':
                    converted = int(self.from_entry_variable.get()) * self.jy_to_other_list[2]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Pakistani Rupee':
                    converted = int(self.from_entry_variable.get()) * self.jy_to_other_list[3]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Swiss Franc':
                    converted = int(self.from_entry_variable.get()) * self.jy_to_other_list[4]
                    self.to_entry_variable.set(value=f'{converted}')

                elif self.to_currency.get() == 'Japanese Yen':
                    converted = int(self.from_entry_variable.get()) * self.jy_to_other_list[5]
                    self.to_entry_variable.set(value=f'{converted}')

        except TclError:
            pass


root = CurrencyConverter()
root.mainloop()

标签： pythontkinterdata-structures

Answer 1

像这样的一些功能（我没有 Python 编译器 - 可能存在小错误）？

 currencies_list = ['United States Dollar', 'Pound Sterling', 'Euro', 'Pakistani Rupee', 'Swiss Franc', 'Japanese Yen']
    usd_to_other_list = [1, 0.72, 0.85, 153.5, 0.94, 110.7]
    
    def GetParity(ValueToConvert, FromCurrency, ToCurrency):
        SourceIndex = currencies_list.Index(FromCurrency)
    
        DestIndex = currencies_list.Index(ToCurrency)
    
        SourceR = usd_to_other_list(SourceIndex)
    
        DestR = usd_to_other_list(DestIndex)
    
        Result = ValueToConvert * DestR / SourceR
        Return(Result)