温度转换器问题

Question

我正在使用GUI（即Tkinter模块）为我的第一个主项目制作温度转换器。初始化GUI时没有任何问题。这很好（据我所知）。我需要一些帮助，使IF语句调用与转换相关的每个函数。我遇到的问题是我不知道如何在两个不同的列表中显示两个项目之间的等效性。这是我的代码（我知道我遗漏了一些东西。显然是if语句。）

from tkinter import *

gui = Tk()
gui.title(string='Temperature Converter')
#create the GUI
fromUnit = StringVar()
#variable which holds the value of which unit is active in "units1"
toUnit = StringVar()
#variable which holds the value of which unit is active in "units2"
initialTemp = StringVar()
#the initial temperature entered in "enterTemp" entry
initialTemp.set('0')
#set the initial temperature to 0
convertedTemp = StringVar()
#used to display the converted temperature through "displayTemp" 
convertedTemp.set('0')
#set the converted temperature to 0

units1 = ('Celsius', 'Fahrenheit', 'Kelvin') #the units used in the OptionMenu
units2 = ('Celsius', 'Fahrenheit', 'Kelvin')

fromUnit.set(units1[0]) #set the active element to the item in index[0] of units1
toUnit.set(units2[0]) #set the active element to the item in index[0] of units2

# celsius-celcius conversion
def celsius_to_celsius():
    currentTemp = float(initialTemp.get())
    convertedTemp.set(currentTemp)

# celsius-kelvin conversion
def celsius_to_kelvin():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp + 273.15)
    convertedTemp.set(currentTemp)

# celsius-fahrenheit conversion
def celsius_to_fahrenheit():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp * (9/5))+32
    convertedTemp.set(currentTemp)

#fahrenheit-fahrenheit conversion
def fahrenheit_to_fahrenheit():
    currentTemp = float(initialTemp.get())
    convertedTemp.set(currentTemp)

#fahrenheit-celsius conversion
def fahrenheit_to_celsius():
    currentTemp = float(initialTemp.get())
    currentTemp = ((currentTemp - 32)*(5/9))
    convertedTemp.set(currentTemp)

#fahrenheit-kelvin conversion
def fahrenheit_to_kelvin():
    currentTemp = float(initialTemp.get())
    currentTemp = ((currentTemp - 32)*(5/9)+273.15)
    convertedTemp.set(currentTemp)

#kelvin-kelvin conversion
def kelvin_to_kelvin():
    currentTemp = float(initialTemp.get())
    convertedTemp.set(currentTemp)

#kelvin-celsius conversion
def kelvin_to_celsius():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp - 273.15)
    convertedTemp.set(currentTemp)

#kelvin-fahrenheit conversion
def kelvin_to_fahrenheit():
    currentTemp = float(initialTemp.get())
    currentTemp = (((currentTemp - 273.15)*(9/5))+32)
    convertedTemp.set(currentTemp)

#main function
#contains the if statements which select which conversion to use
def convert_Temp():
    currentTemp = float(initialTemp.get())
    if (fromUnit, toUnit) == ('Celsius','Celsius'):
        celsius_to_celsius()


gui.geometry('+100+100')
#set up the geometry

enterTemp = Entry(gui,textvariable=initialTemp,justify=RIGHT)
enterTemp.grid(row=0,column=0)
#Entry which receives the temperature to convert

convertFromUnit = OptionMenu(gui,fromUnit,*units1)
convertFromUnit.grid(row=0,column=1)
#Option Menu which selects which unit to convert from

displayTemp = Label(gui,textvariable=convertedTemp)
displayTemp.grid(row=1,column=0)
#Label which displays the temperature
#Takes text variable "convertTemp"

convertToUnit = OptionMenu(gui,toUnit,*units2)
convertToUnit.grid(row=1,column=1)
#Option Menu which selects which unit to convert to

convertButton = Button(gui,text='Convert',command=convert_Temp)
convertButton.grid(row=2,column=1)
#Button that starts the conversion
#Calls the main function "convert_Temp"

gui.mainloop()
#End of the main loop

感谢您查看以及您提供的任何帮助和批评。没有浪费任何知识！ 干杯

Answer 1

正如评论中所指出的，你有一些架构缺陷（这是正常的，因为你正在学习），你可能会从CodeReview社区获得有趣的反馈（它是stackexchange网络的另一个站点）。 / em>的

这里有一些选项可用于执行您所谓的 If语句。你这个事实 已经包含在函数中的转换拓宽了可能性。

1）枚举if

中的所有组合

你已经开始了，但有所不同：使用fromUnit.get()来访问tkinter变量 ¹ 的值。

if (fromUnit.get(), toUnit.get()) == ('Celsius','Celsius'):
    celsius_to_celsius()
if (fromUnit.get(), toUnit.get()) == ('Celsius','Fahrenheit'):
    celsius_to_fahrenheit()
if (fromUnit.get(), toUnit.get()) == ('Celsius','Kelvin'):
    celsius_to_kelvin()

2）嵌套if

if fromUnit.get() == 'Celsius':
    if toUnit.get()) == 'Celsius':
        celsius_to_celsius()
    if toUnit.get()) == 'Fahrenheit':
        celsius_to_fahrenheit()
    if toUnit.get()) == 'Kelvin':
        celsius_to_kelvin()

3）使用字典（associative arrray）来存储函数

converters = {
    'Celsius' : {
        'Celsius' : celsius_to_celsius,
        'Fahrenheit': celsius_to_fahrenheit,
        'Kelvin': celsius_to_kelvin},
    'Fahrenheit' : {
        'Celsius' : fahrenheit_to_celsius,
        'Fahrenheit': fahrenheit_to_fahrenheit,
        'Kelvin': fahrenheit_to_kelvin},
    #...
}
#retrieve function, and call it (through the () at the end)
converters [fromUnit.get()] [toUnit.get()] ()

实际上，它使用嵌套字典。您也可以只使用一个字典

converters = {
    ('Celsius', 'Celsius') : celsius_to_celsius,
    ('Celsius', 'Fahrenheit'): celsius_to_fahrenheit,
    ('Celsius', 'Kelvin'): celsius_to_kelvin,
}
converters [(fromUnit.get(), toUnit.get())] ()

4）您使用的一致命名方案允许生成函数名称

function_name = fromUnit.get().lower() + "_to_" + toUnit.get().lower()
globals()[function_name] ()

5）委派发货

通常情况下，大型组合if（或切换语言存在）是对重构的吸引力。 例如，您可能会在convertFromUnit或fromUnit（分别为*toUnit）上进行初步工作。

使用嵌套字典的机制与Python对象中使用的机制非常接近。

def fromUnitCallback():
    global _converter
    _converter = globals()[fromUnit.get()]()

def toUnitCallback():
    global _function_name
    _function_name = toUnit.get().lower()

def convert_Temp():
    currentTemp = float(initialTemp.get())
    _converter.set(currentTemp)
    converted = getattr(_converter, _function_name) ()
    convertedTemp.set(converted)

class Kelvin:
    def __init__(self, val=0):
        self.__kelvin = val

    def kelvin(self):
        return self.__kelvin

    def celsius(self):
        return self.__kelvin - 273.15

    def fahrenheit(self):
        return (self.__kelvin - 273.15)*1.8 + 32

    def set(self, val):
        self.__kelvin = val

class Celsius(Kelvin):
    def __init__(self, val):
        Kelvin.__init__(self)
        self.set(val)

    def set(self, val):
        Kelvin.set(self, val + 273.15)

class Fahrenheit:
    def __init__(self, val):
        Kelvin.__init__(self)
        self.set(val)

    def set(self, val):
        Kelvin.set((val - 32)*5/9 + 273.15)

<小时/> ¹ Tkinter变量是对象，即复合伪影嵌入值和相关方法。服务于常规变量的相同目的，除了它们可以是traced之外，可以警告它们的值已经改变。它们与tkinter小部件结合使用以简化操作。在这里，您想要将fromUnit的内容与文字字符串'Celsius'进行比较，因此您必须通过fromUnit方法询问get字符串。有关详细信息，请参阅http://effbot.org/tkinterbook/variable.htm

Answer 2

这是我上面开始的程序的最终源代码。

from tkinter import *

gui = Tk()
gui.title(string='Temperature Converter')
#create the GUI
fromUnit = StringVar()
#variable which holds the value of which unit is active in "units1"
toUnit = StringVar()
#variable which holds the value of which unit is active in "units2"
initialTemp = StringVar()
#set the initial temperature to 0
convertedTemp = StringVar()
#used to display the converted temperature through "displayTemp" 
convertedTemp.set('0')
#set the converted temperature to 0

units1 = ('Celsius', 'Fahrenheit', 'Kelvin') #the units used in the OptionMenu
units2 = ('Celsius', 'Fahrenheit', 'Kelvin')

fromUnit.set(units1[0]) #set the active element to the item in index[0] of units1
toUnit.set(units2[0]) #set the active element to the item in index[0] of units2

#main function
#contains the if statements which select which conversion to use
def convert_Temp():
    currentTemp = float(initialTemp.get())
    cu1 = fromUnit.get()
    cu2 = toUnit.get()

    if (cu1, cu2) == ('Celsius', 'Celsius'):
        c_c()
    elif (cu1, cu2) == ('Celsius', 'Kelvin'):
        c_k()
    elif (cu1, cu2) == ('Celsius', 'Fahrenheit'):
        c_f()
    elif (cu1, cu2) == ('Fahrenheit', 'Fahrenheit'):
        f_f()
    elif (cu1, cu2) == ('Fahrenheit', 'Celsius'):
        f_c()
    elif (cu1, cu2) == ('Fahrenheit', 'Kelvin'):
        f_k()
    elif (cu1, cu2) == ('Kelvin', 'Kelvin'):
        k_k()
    elif (cu1, cu2) == ('Kelvin', 'Celsius'):
        k_c()
    elif (cu1, cu2) == ('Kelvin', 'Fahrenheit'):
        k_f()
    else:
        messagebox.showerror(title='ERROR', message='Error in the IF statements')

# celsius-celcius conversion
def c_c():
    currentTemp = float(initialTemp.get())
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

# celsius-kelvin conversion
def c_k():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp + 273.15)
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

# celsius-fahrenheit conversion
def c_f():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp * (9/5))+32
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

#fahrenheit-fahrenheit conversion
def f_f():
    currentTemp = float(initialTemp.get())
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

#fahrenheit-celsius conversion
def f_c():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp - 32)*(5/9)
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

#fahrenheit-kelvin conversion
def f_k():
    currentTemp = float(initialTemp.get())
    currentTemp = ((currentTemp - 32)*(5/9)+273.15)
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

#kelvin-kelvin conversion
def k_k():
    currentTemp = float(initialTemp.get())
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

#kelvin-celsius conversion
def k_c():
    currentTemp = float(initialTemp.get())
    currentTemp = (currentTemp - 273.15)
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)

#kelvin-fahrenheit conversion
def k_f():
    currentTemp = float(initialTemp.get())
    currentTemp = (((currentTemp - 273.15)*(9/5))+32)
    currentTemp = round(currentTemp, 2)
    convertedTemp.set(currentTemp)


gui.geometry('+100+100')
#set up the geometry

enterTemp = Entry(gui,textvariable=initialTemp,justify=RIGHT)
enterTemp.grid(row=0,column=0)
#Entry which receives the temperature to convert

convertFromUnit = OptionMenu(gui,fromUnit,*units1)
convertFromUnit.grid(row=0,column=1)
#Option Menu which selects which unit to convert from

displayTemp = Label(gui,textvariable=convertedTemp)
displayTemp.grid(row=1,column=0)
#Label which displays the temperature
#Takes text variable "convertTemp"

convertToUnit = OptionMenu(gui,toUnit,*units2)
convertToUnit.grid(row=1,column=1)
#Option Menu which selects which unit to convert to

convertButton = Button(gui,text='Convert',command=convert_Temp)
convertButton.grid(row=2,column=1)
#Button that starts the conversion
#Calls the main function "convert_Temp"

gui.mainloop()
#End of the main loop