tkinter (python) 中的文件夹路径问题

Question

我遇到了使用 filedialog 在代码中查找与文件夹路径相关的错误的问题。 我有以下代码

import tkinter
import tkinter.ttk
from tkinter import filedialog
from tkinter import *
global user_input
def create_widgets_in_first_frame():
# Create the label for the frame
first_window_label = tkinter.ttk.Label(first_frame, text='Window 1')
first_window_label.grid(column=0, row=0, pady=10, padx=10, sticky=(tkinter.N))
folder_path = StringVar()
# Create the button for the frame
first_window_quit_button = tkinter.Button(first_frame, text = "Quit", command = quit_program)
first_window_quit_button.grid(column=1, row=1, pady=10, sticky=(tkinter.N))
#var = IntVar()
entry1 = tkinter.Entry(first_frame)
entry1.grid(column=0, row=1, pady=10,sticky=(tkinter.N))
user_input = entry1.get()
first_window_diffbutton = tkinter.Button(first_frame, text="Price difference",command=avgprice)
first_window_diffbutton.grid(column=2, row=1, pady=10,sticky=(tkinter.N))
def browse_button():
# Allow user to select a directory and store it in global var
# called folder_path
global folder_path
filename = filedialog.askdirectory()
folder_path.set(filename)
return filename   
def call_first_frame_on_top():
# This function can be called only from the second window.
# Hide the second window and show the first window.
second_frame.grid_forget()
first_frame.grid(column=0, row=0, padx=20, pady=5, sticky=(tkinter.W, tkinter.N, tkinter.E))

def quit_program():
root_window.destroy()
def avgprice():
path1=browse_button()
size=user_input
import pandas as pd
from pathlib import Path
import glob
import os
import matplotlib.pyplot as plt
import numpy as np
import csv
path = Path(path1)
filenames = glob.glob(path1 + "/*.csv")
%matplotlib inline
for filename in filenames:
headers = ['time', 'size', 'price', 'type']
dtypes = {'time': 'str', 'size': 'float', 'price': 'float','type': 'str'}
parse_dates = ['time']
parse_dates = ['time']
btcnow = pd.read_csv(filename, header=None, names=headers, dtype=dtypes, parse_dates=parse_dates)
now3 = pd.DataFrame(btcnow, columns=['size','time','unix','price'])
now4=now3[['time','price','size']]
df6= now4.loc[now4["size"] == size,'size']
df7= now4.loc[now4["size"] == size, "time"]
df8= now4.loc[now4["size"] == size, "price"]
result1= [df6,df7,df8]
result1 = pd.concat(result1, axis=1, sort=True)
result1.columns = ['size','orig_time','price']
df10=result1.groupby('orig_time').last().reset_index()
df10 = df10[['size','orig_time','price']]
from datetime import datetime, timedelta
time_interval = timedelta(minutes = 5)
df = now3[[ 'time', 'size', 'price']]
# extract time size for merge
df_time_size=df.loc[:, ['time', 'size']].copy()
df_time_size.loc[:, 'time'] = df_time_size.loc[:, 'time'] + time_interval
# inner join dataframe by size&time
df = df_time_size.merge(df[['time', 'size', 'price']], how = 'inner')
df['orig_time'] = df['time'] - time_interval
df=df.groupby('time').last().reset_index()
df1= df.loc[df["size"] == size, "price"]
df2= df.loc[df["size"] == size, "time"]
df3= df.loc[df["size"] == size, "size"]
df4=df.loc[df["size"] == size, "orig_time"]
frames = [df3,df1,df2,df4]
result = pd.concat(frames, axis=1, sort=True)
a=pd.merge(result,df10, on="orig_time")
b=a[['size_x' ,'price_x','time','orig_time','price_y']].copy()
b.rename(columns = {'size_x':'size' ,'price_x':'price','time':'time','orig_time':'orig_time','price_y':'orig_price'}, inplace = True) 
b['diff']=abs(b['price']-b['orig_price'])
list1=[]
list1=(b['diff'])
print('size', size, list1)

###############################
# Main program starts here :) #
###############################
# Create the root GUI window.
root_window = tkinter.Tk()
# Define window size
window_width = 200
window_heigth = 100
# Create frames inside the root window to hold other GUI elements. All frames must be created in the main program, otherwise they are not accessible in functions. 
first_frame=tkinter.ttk.Frame(root_window, width=window_width, height=window_heigth)
first_frame['borderwidth'] = 2
first_frame['relief'] = 'sunken'
first_frame.grid(column=0, row=0, padx=20, pady=5, sticky=(tkinter.W, tkinter.N, tkinter.E))

# Create all widgets to all frames
create_widgets_in_first_frame()
# Hide all frames in reverse order, but leave first frame visible (unhidden).

# Start tkinter event - loop
root_window.mainloop()

将显示以下错误：

Exception in Tkinter callback
Traceback (most recent call last):
File "C:UsersNatalieAnaconda3libtkinter__init__.py", line 1705, in __call__
return self.func(*args)
File "<ipython-input-8-e64cca04b689>", line 42, in avgprice
path1=browse_button()
File "<ipython-input-8-e64cca04b689>", line 27, in browse_button
folder_path.set(filename)
NameError: name 'folder_path' is not defined

Answer 1

使用

folder_path.set(...)

你必须首先创建

folder_path = StringVar()

global不会创建变量，但它仅在函数中用于在函数中通知此函数在您使用=赋值(而不是创建局部变量(时使用外部/全局变量。

您将遇到同样的问题user_input.

所以你可以在开始时创建变量

root_window = tkinter.Tk()
user_input = ''   # it creates global variable
folder_path = StringVar()  # it creates global variable

它解决了这些变量的问题

---

编辑：我发现您在create_widgets_in_first_frame中使用folder_path = StringVar()，但它创建了局部变量。您必须使用global来通知函数以将StringVar()分配给外部/glboal 变量

def create_widgets_in_first_frame():
global folder_path  # inform function to assign value (`=`) to external variable `folder_path`
folder_path = StringVar()

然后它将创建全局folder_path，您不必在开始时创建它。