python tkinter 匯率換算器

其實我最近正在學pyqt，然後看到有個例子是匯率換算器，所以無聊之下換成用tkinter來寫寫看code如下

def test2():
    import tkinter
    from tkinter import ttk

    rates = {}

    def getdata():
        nonlocal rates
        try:
            date = 'unknown'
            fh = request.urlopen("http://www.bankofcanada.ca/en/markets/csv/exchange_eng.csv")
            #always remember that in python3 this function returns byte object!!
            for line in fh:
                line = line.decode('utf-8')# so need to decode
                if not line or line.startswith(('#', "Closing ")):
                    continue
                fields = line.split(',')
                if line.startswith("Date "):
                    date = fields[-1]
                else:
                    try:
                        value = float(fields[-1])
                        rates[fields[0]] = value
                    except ValueError:
                        pass
            return "Exchange Rates Date: "+ date
        except Exception as e:
            return "Failed to downloads:\n%s" % e

    def show(event):
        try:
            num = float(entry.get())
        except:
            pass

        fromCur = float(rates[fromCombo.get()])
        toCur = float(rates[toCombo.get()])
        result['text'] = fromCur/toCur * num


    root = tkinter.Tk()

    dateLabel = ttk.Label(root, text=getdata())
    listVar = sorted(rates.keys())


    fromCombo = ttk.Combobox(root, values=listVar, state='readonly')
    fromCombo.current(0)
    toCombo = ttk.Combobox(root, values=listVar, state='readonly')
    toCombo.current(0)

    entry = tkinter.Entry(root)
    result = ttk.Label(root, text='...')

    calculate = ttk.Button(root, text='calculate')
    calculate.bind('<Button-1>', show)


    dateLabel.grid(column=0, row=0, columnspan=2, padx=5)
    fromCombo.grid(column= 0, row=1, padx=10, pady=5)
    toCombo.grid(column=0, row=2, padx=10, pady=5)
    entry.grid(column=1, row=1, padx=10, pady=5)
    result.grid(column=1, row=2, padx=10, pady=5)
    calculate.grid(column=0, row=3, columnspan=2)
    
    root.mainloop()


if __name__ == '__main__':
    test2()

由於只是嘗試寫寫所以就沒有特別去想結構了，用了不怎麼好看的寫法 :)

只是有個地方滿好奇的，我用這匯率去算跟台銀給的匯率計算器得出的結果不一樣(汗，不過其實我也不太懂匯率是怎麼得出來的，所以用這個程式得出來的結果看看就好，想要知道目前的匯率還是去台銀官網看吧 :) 或者就是把這篇code所抓取的csv改成台銀的 :)

Posted in python