python 中的应用程序以及 BeautifulSoup

我的目标是创建一个简单的应用程序为基础的计算器-从一种货币到另一种货币转换，但事情是，转换率应该自动从网站检索.为此，我决定使用kivy库.基于以下示例: kivy calculator个 我设法更改了一些小部分，得到了以下代码和结果:

以下是.py文件和.kv文件的代码

`import kivy

# base Class of your App inherits from the App class.
# app:always refers to the instance of your application
from kivy.app import App

# this restrict the kivy version i.e
# below this kivy version you cannot
# use the app or software
kivy.require('1.9.0')

# for making multiple buttons to arranging
# them we are using this
from kivy.uix.gridlayout import GridLayout

# for the size of window
from kivy.config import Config

# Setting size to resizable
Config.set('graphics', 'resizable', 1)


## Config.set('graphics', 'width', '400')
## Config.set('graphics', 'height', '400')


# Creating Layout class
class CalcGridLayout(GridLayout):

    # Function called when equals is pressed
    def calculate(self, calculation):
        if calculation:
            try:
                # Solve formula and display it in entry
                # which is pointed at by display
                self.display.text = str(eval(calculation))
            except Exception:
                self.display.text = "Error"


# Creating App class
class CalculatorApp(App):

    def build(self):
        return CalcGridLayout()


# creating object and running it
calcApp = CalculatorApp()
calcApp.run()`

和相应的.kv文件

<CustButton@Button>:
    font_size: 32

# Define id so I can refer to the CalcGridLayout
# class functions
# Display points to the entry widget

``<CalcGridLayout>:
    id: calculator
    display: entry
    rows: 6
    padding: 10
    spacing: 10



    # Where input is displayed
    BoxLayout:
        TextInput:
            id: entry
            font_size: 32
            multiline: False

    # When buttons are pressed update the entry
    BoxLayout:
        spacing: 10
        CustButton:
            text: "7"
            on_press: entry.text += self.text
        CustButton:
            text: "8"
            on_press: entry.text += self.text
        CustButton:
            text: "9"
            on_press: entry.text += self.text
        CustButton:
            text: "$"
            on_press: entry.text =entry.text+'/'+ str(2.54)

    BoxLayout:
        spacing: 10
        CustButton:
            text: "4"
            on_press: entry.text += self.text
        CustButton:
            text: "5"
            on_press: entry.text += self.text
        CustButton:
            text: "6"
            on_press: entry.text += self.text
        CustButton:
            text: "yen"
            on_press: entry.text =entry.text+'*'+ str(54.21)

    BoxLayout:
        spacing: 10
        CustButton:
            text: "1"
            on_press: entry.text += self.text
        CustButton:
            text: "2"
            on_press: entry.text += self.text
        CustButton:
            text: "3"
            on_press: entry.text += self.text
        CustButton:
            text: "euro"
            on_press: entry.text =entry.text+'/'+ str(2.8070)

    # When equals is pressed pass text in the entry
    # to the calculate function
    BoxLayout:
        spacing: 10
        CustButton:
            text: "AC"
            on_press: entry.text = ""
        CustButton:
            text: "0"
            on_press: entry.text += self.text
        CustButton:
            text: "="
            on_press: calculator.calculate(entry.text)
        CustButton:
            text: "GBP"
            on_press: entry.text =entry.text+'/'+ str(3.1790)
    BoxLayout:
        CustButton:
            font_size: 20
            text: "Scientific calculator"
            on_press: entry.text = ""

`

当我运行.py文件时，我得到以下结果: result of my code个

但问题是，如果我们查看代码: text: "GBP" on_press: entry.text =entry.text+'/'+ str(3.1790)个 GBP是静态的，如果我想用美汤从网络上获取这些数据，如何将结果结合到我们的课堂上？请给我一个提示

编辑:由于之前的问题有不清楚的 comments ，也就是我问的问题不清楚，我将重复问题: 请看下面的代码:

 text: "GBP"
            on_press: entry.text =entry.text+'/'+ str(3.1790)

除了直接写汇率，我如何从网站上读取它并将其包含在Kivy中，这里有什么不清楚的？例如，请查看以下链接: Exchange rates个

你能看到关于英镑的信息吗？如何获得这一点，并包括在猕猴桃？我知道我可以通过美味的汤得到它，但是如何包含在猕猴桃中，现在清楚了吗？