python - 在 lambda 函数中将多个函数作为参数传递不起作用

Question

这两个函数在计算糖果价格的 lamba 函数中不能作为 args 工作

def mysweets():
    b = v.get( ) # get the value of v set
    cost=int(mysweets_price_list[b]) #price_display
    print(cost)



def quantity_sweets():
    q = int(spinbox1.get())
    print(q)

price = lambda b, q : b * q # final price to be displayed in myLabel_3

print(price(b, q))

我已经尝试过嵌套函数，但它们不起作用，请帮助任何人

from tkinter import *

myGui = Tk()
myGui.geometry('450x450+200+200')
myGui.title('Auto Sweet Dispenser')

price_display = ""
b = 0
#a = 0
q = 0
mysweets_price_list = {1 :9.00,
                      2 :7.50,
                      } # dict for the sweet prices

def mysweets():
    b = v.get( ) # get the value of v set
    cost=int(mysweets_price_list[b]) #price_display
    print(cost)



def quantity_sweets():
    q = int(spinbox1.get())
    print(q)

price = lambda b, q : b * q # final price to be displayed in myLabel_3

print(price(b, q))


v =IntVar()
price =IntVar()
v.set(1)

myLabel = Label(myGui,text = 'Choose your sweets',font = 14, fg ='brown').place(x=140,y=55)#grid(row=3,column=10,sticky = 'e')

myRadio_1 = Radiobutton(myGui,text = 'Mints',variable = v, value = 1, command = mysweets).place(x= 160, y = 100)
myRadio_2 = Radiobutton(myGui,text = 'Nut log',variable = v, value = 2, command = mysweets).place(x= 160, y = 120)


myLabel_2 = Label(myGui,text = 'Select Quantity',font = 12, fg ='brown').place(x=160,y=160)#grid(row=3,column=10,sticky = 'e')

myLabel_3 = Label(myGui,textvariable = price ,font = "Times 14 bold",width = 14, fg ='white', bg= 'blue' ,relief = RAISED).place(x=160,y=220)#grid(row=3,column=10,sticky = 'e')


spinbox1 = Spinbox(myGui,from_=1,to = 6,command = quantity_sweets, state = NORMAL)
spinbox1.place(x=160,y=180)#



myGui.mainloop()

该代码有效，只是由于 lambda 函数不工作而没有显示价格。

标签： pythontkinterlambda

Answer 1

您在这里不需要 lambda（通常 lambda 应该非常罕见）。您只需要一个函数即可获取所有数据、进行计算并更新标签。像这样：

from tkinter import *

myGui = Tk()
myGui.geometry('450x450+200+200')
myGui.title('Auto Sweet Dispenser')

mysweets_price_list = {1 :9.00,
                      2 :7.50,
                      } # dict for the sweet prices

def calculate():
    b = v.get( ) # get the value of v set
    cost=mysweets_price_list[b] #price

    q = int(spinbox1.get()) # get quantity.

    final_price = cost * q # final price to be displayed
    price.set(final_price)

v =IntVar(value=1) # set initial value to 1
price = IntVar()

Label(myGui,text = 'Choose your sweets',font = 14, fg ='brown').place(x=140,y=55)#grid(row=3,column=10,sticky = 'e')

Radiobutton(myGui,text = 'Mints',variable = v, value = 1, command = calculate).place(x= 160, y = 100)
Radiobutton(myGui,text = 'Nut log',variable = v, value = 2, command = calculate).place(x= 160, y = 120)

Label(myGui,text = 'Select Quantity',font = 12, fg ='brown').place(x=160,y=160)#grid(row=3,column=10,sticky = 'e')

Label(myGui,textvariable = price ,font = "Times 14 bold",width = 14, fg ='white', bg= 'blue' ,relief = RAISED).place(x=160,y=220)#grid(row=3,column=10,sticky = 'e')

spinbox1 = Spinbox(myGui,from_=1,to = 6,command = calculate, state = NORMAL)
spinbox1.place(x=160,y=180)

calculate() # do the calculation at boot
myGui.mainloop()

此外，非常重要的是要知道，如果您这样做，name = Widget().place()那么名称将被设置None为无用。你需要做

name = Widget()
name.grid() # or pack() or place()

或者

Widget().grid() # or pack() or place()

不要混合这两种风格！2-line的样式要好很多，和我们平时用的一样。