使用Tkinter在python中创建POS系统现在我有这个错误

Question

我只是在每次按下"Americano"键时为我的POS系统创建收据函数和计算函数。按钮，它应该将其添加到treeviewer列表它确实这样做了但它没有在UI底部添加价格

这是我的功能

def Coffee1():
ItemCost = 3.70
GST = 2.5
self.POS_records.insert("", tk.END, values= ("Americano", "1", "3.70"))
for child in self.POS_records.get_children():
ItemCost += float(self.POS_records.item(child, "values")[2])
SubTotal_Input.set(str('$%.2f'%(ItemCost - 3.7)))
GST_Input.set(str('$%.2f'%(ItemCost - 2) * GST/100))
Total_Input.set(str('$%.2f'%(ItemCost -3.7) + (ItemCost - 3) * GST/100))

这是我按美式按钮时得到的错误

File "c:UserscalluDocumentsMajor ProjectMajor test-1.py", line 129, in Coffee1
GST_Input.set(str('$%.2f'%(ItemCost - 2) * GST/100))
TypeError: can't multiply sequence by non-int of type 'float
PS C:UserscalluDocumentsMajor Project> 

Answer 1

请尝试一下。

def Coffee1():
ItemCost = 3.70
GST = 2.5
self.POS_records.insert("", tk.END, values= ("Americano", "1", "3.70"))
for child in self.POS_records.get_children():
ItemCost += float(self.POS_records.item(child, "values")[2])
SubTotal_Input.set(str('$%.2f'%(ItemCost - 3.7)))
GST_Input.set(str('$%.2f'%((ItemCost - 2) * GST/100)))
Total_Input.set(str('$%.2f'%((ItemCost -3.7) + (ItemCost - 3) * GST/100)))

我想，有语法问题。你可以看到两者的区别。

GST_Input.set(str('$%.2f'%(ItemCost - 2) * GST/100))
GST_Input.set(str('$%.2f'%((ItemCost - 2) * GST/100)))