如何使用tkinter修复Python中的“ ValueError：无法将字符串转换为float：”

Question

I'm using tkinter interface with Python 3.7.2, and it gives out:

ValueError: could not convert string to float:

I need to take content from Edit's and multiply them by showing them on Label .

I tried using int but I'm using number '2.5'

def count():
    x = float(EditBox1_text.get())
    y = float(EditBox2_text.get())
    return x * y

EditBox1_text = StringVar(0)
EditBox2_text = StringVar(0)

EditBox1 = Entry(MainActivity, textvariable=EditBox1_text).grid(row=0, column=0, sticky=W)
EditBox2 = Entry(MainActivity, textvariable=EditBox2_text).grid(row=1, column=0, sticky=W)

Answer 1

I'm tried this, and it's worked:

def count():
    x = float(EditBox1_text.get())
    y = float(EditBox2_text.get())
    AnswerText_text.set(x * y)

Before, i called

AnswerText_text.set(count())

At run of code

Answer 2

Tkinter constructor of StringVar takes no value argument, unless if pointed as a keyword argument, as pointed by @BryanOakley, So, you cannot initialize StringVar with a value without the keyword argument declared. For that you have to use .set , to set the variable value, as so:

EditBox1_text = StringVar()
EditBox2_text = StringVar()

EditBox1_text.set("2.5")
EditBox2_text.set("3.8")