我已经创建了一个GUI,你可以手动输入值(x值)。如果你输入一个值x1,trace-method将自动计算出
f(x1)=x1^2=y1,则平均数(y)=(15 sum_{i=1}^{5} y_i)
所以每输入一个x值,就会计算出相应的y值和平均值(y)。下面的代码可以用。如果你启动它,你会得到。
我想从一些单元格中删除0. 0的初始值。代码执行后,窗口应该是这样的。
为了得到想要的结果,我在最后添加了以下内容 mainloop()
for i in range(1,5):
y_values[i].set("")
cells[(i,0)].delete(0,END)
其中我删除了某些单元格的初始值。如果你在启动代码时做了这样的改变,程序将不再正常工作。如果你输入一个x值,只计算相应的y值,而不是平均数(y)。
你们有谁知道为什么用 y_values[i].set("")
, cells[(i,0)].delete(0,END)
不再正常工作,如何解决这个问题?
这里是完整的代码(从图片1)。
from tkinter import *
import tkinter as tk
root = Tk()
Label(root, text = "x-values",padx = 10).grid(row = 0, column = 0)
Label(root, text = "y-values",padx = 10).grid(row = 0, column = 1)
Label(root, text = "Mean y", padx = 10).grid(row = 0, column = 2)
# Create Variables
x_values, y_values = ["x%d" % x for x in range(5)], ["y%d" % x for x in range(5)]
for i in range (5):
x_values[i], y_values[i] = DoubleVar(), DoubleVar()
mean = DoubleVar()
# Create Table
rows, columns, cells = 5, 2, {}
for i in range(columns):
for j in range(rows):
if i == 0: # x-values that can be entered
b = Entry(root, textvariable=x_values[j])
b.grid(row = j+1, column = i, sticky = W + E)
cells[(j,i)] = b
else: # y-values that are computed by f
b = Label(root, textvariable=y_values[j])
b.grid(row = j+1, column = i, sticky = W + E)
cells[(j,i)] = b
label_mean = Label(root, textvariable = mean).grid(row = 1, column = 2, rowspan = 5)
# compute y-values
def f(name, index, mode):
try:
for i in range(5):
y_values[i].set(x_values[i].get()**2)
except tk.TclError:
pass
# compute mean and standard deviation
def statistic(name, index, mode):
try:
y_sum = 0
for i in range(5):
y_sum += y_values[i].get()
y_normalized = y_sum / 5
mean.set(y_normalized)
except tk.TclError:
pass
# Traces to trigger the above functions
for i in range(5):
x_values[i].trace('w', f)
y_values[i].trace('w', statistic)
mainloop()
平均数没有计算出来,因为当你试图将None值添加到 y_sum
. 增加 try
拦住 statistics
职能。
def statistic(name, index, mode):
try:
y_sum = 0
for i in range(5):
try:
y_sum += y_values[i].get()
except:
pass
y_normalized = y_sum / 5
mean.set(y_normalized)
except tk.TclError:
pass