如何在 Python 中的嵌套 function 中调用 function

Question

I am just starting to learn programming. I am trying to define a function in python so that I wouldn't have to repeat code in my program. This program searches entries from database and displays either all entries or entries containing keyword. Here is my program stripped down for the context of this question, that works as I intended:

from tkinter import *

import sqlite3
from tkinter import ttk
    

    root = Tk()
    root.title('Program')
    
    def search():
        search_window = Toplevel(root)
        search_window.title('Program - Search')
    def search_all():
        searchresult_window = Tk()
        searchresult_window.title('Program - Searchresult')

        #Checks the number of searchresults
        conn = sqlite3.connect('database.db')
        c = conn.cursor()
        c.execute('SELECT COUNT() FROM entry_table')
        number = int(str(c.fetchone()).replace(",","").replace("(","").replace(")",""));

        #Gets data from database
        c.execute('SELECT * FROM entry_table')
        data = c.fetchall()
        row_count = 0

        # Scrollbar
        main_frame = Frame(searchresult_window)
        main_frame.pack(fill=BOTH, expand=1)
        my_canvas = Canvas(main_frame)
        my_canvas.pack(side=LEFT, fill=BOTH, expand=1)
        my_scroblbar = ttk.Scrollbar(main_frame, orient=VERTICAL, command=my_canvas.yview)
        my_scroblbar.pack(side=RIGHT, fill=Y)
        my_canvas.configure(yscrollcommand=my_scroblbar.set)
        my_canvas.bind('<Configure>', lambda e: my_canvas.configure(scrollregion=my_canvas.bbox("all")))
        seccond_frame = Frame(my_canvas)
        my_canvas.create_window((0, 0), window=seccond_frame, anchor="nw")

        # Displays searchresults on screen
        for _ in range(number):
            searchresult_frame = LabelFrame(seccond_frame, pady=5, bg='yellow1')
            searchresult_frame.pack()
            data_label = Label(hakutulos_frame, text=data[row_count][1], borderwidth=5, relief="groove", width=10)
            data_label.grid(row=0, column=0)

            row_count = row_count + 1

        c.close
        conn.close()
        search_window.destroy()
        searchresult_window.lift()

    def search_by_keyword():
        searchresult_window = Tk()
        searchresult_window.title('Program - Searchresult')

        #Checks the number of searchresults
        given_keyword = keyword.get()
        conn = sqlite3.connect('database.db')
        c = conn.cursor()
        c.execute("SELECT COUNT() FROM entry_table WHERE subject LIKE '%'||?||'%' OR header LIKE '%'||?||'%' OR entry LIKE '%'||?||'%'",
                  (given_keyword, given_keyword, given_keyword))
        number = int(str(c.fetchone()).replace(",","").replace("(","").replace(")",""));

        #Gets data from database
        c.execute("SELECT * FROM entry_table WHERE subject LIKE '%'||?||'%' OR header LIKE '%'||?||'%' OR entry LIKE '%'||?||'%'",
                  (given_keyword, given_keyword, given_keyword))
        data = c.fetchall()
        row_count = 0

        #Scrollbar
        main_frame = Frame(searchresult_window)
        main_frame.pack(fill=BOTH, expand=1)
        my_canvas = Canvas(main_frame)
        my_canvas.pack(side=LEFT, fill=BOTH, expand=1)
        my_scroblbar = ttk.Scrollbar(main_frame, orient=VERTICAL, command=my_canvas.yview)
        my_scroblbar.pack(side=RIGHT, fill=Y)
        my_canvas.configure(yscrollcommand=my_scroblbar.set)
        my_canvas.bind('<Configure>', lambda e: my_canvas.configure(scrollregion = my_canvas.bbox("all")))
        seccond_frame = Frame(my_canvas)
        my_canvas.create_window((0,0), window=seccond_frame, anchor="nw")

        # Displays searchresults on screen
        for _ in range(number):
            searchresult_frame = LabelFrame(seccond_frame, pady=5, bg='yellow1')
            searchresult_frame.pack()
            data_label = Label(searchresult_frame, text=data[row_count][1], borderwidth=5, relief="groove", width=10)
            data_label.grid(row=0, column=0)

        c.close
        conn.close()
        search_window.destroy()
        searchresult_window.lift()

    #Show all button
    all_btn = Button(search_window, text="Show all entries", pady=5, bg='yellow1', command=search_all)
    all_btn.grid(row=0, column=0)

    #Search by keyword frame (including: entry field and search button)
    search_by_keyword_frame = LabelFrame(search_window, text="Search by keyword", pady=5, bg='yellow1')
    search_by_keyword_frame.grid(row=1, column=0)
    keyword = Entry(search_by_keyword_frame)
    keyword.delete(0, END)
    keyword.insert(END, str("Give Keyword"))
    keyword.grid(row=0, column=0)
    hae = Button(search_by_keyword_frame, text="SEARCH", pady=5, bg='yellow1', command=search_by_keyword)
    hae.grid(row=1, column=0)

    return_btn = Button(search_window, text="Return", pady=5, bg='yellow1', command =search_window.destroy)
  

      return_btn.grid(row=2, column=0, pady=5)
    
    
    search_btn = Button(root, text="Search", pady=5, bg='yellow1', command=search)
    search_btn.grid(row=2, column=0, pady=5)
    
    
    root.mainloop()

I realize parts #Scrollbar and #Displays Search results on screen are the exact same and I want to call a function insted of it. However it seems that no matter where I define the function (for scrollbar and Display) I always get error. Here is one example that I have tried:

from tkinter import *
import sqlite3
from tkinter import ttk

root = Tk()
root.title('Program')

def search():
search_window = Toplevel(root)
search_window.title('Program - Search')

def function1():
    # Scrollbar
    main_frame = Frame(searchresult_window)
    main_frame.pack(fill=BOTH, expand=1)
    my_canvas = Canvas(main_frame)
    my_canvas.pack(side=LEFT, fill=BOTH, expand=1)
    my_scroblbar = ttk.Scrollbar(main_frame, orient=VERTICAL, command=my_canvas.yview)
    my_scroblbar.pack(side=RIGHT, fill=Y)
    my_canvas.configure(yscrollcommand=my_scroblbar.set)
    my_canvas.bind('<Configure>', lambda e: my_canvas.configure(scrollregion=my_canvas.bbox("all")))
    seccond_frame = Frame(my_canvas)
    my_canvas.create_window((0, 0), window=seccond_frame, anchor="nw")

    # Displays searchresults on screen
    for _ in range(number):
        searchresult_frame = LabelFrame(seccond_frame, pady=5, bg='yellow1')
        searchresult_frame.pack()
        data_label = Label(hakutulos_frame, text=data[row_count][1], borderwidth=5, relief="groove", width=10)
        data_label.grid(row=0, column=0)

        row_count = row_count + 1

def search_all():
    searchresult_window = Tk()
    searchresult_window.title('Program - Searchresult')

    #Checks the number of searchresults
    conn = sqlite3.connect('database.db')
    c = conn.cursor()
    c.execute('SELECT COUNT() FROM entry_table')
    number = int(str(c.fetchone()).replace(",","").replace("(","").replace(")",""));

    #Gets data from database
    c.execute('SELECT * FROM entry_table')
    data = c.fetchall()
    row_count = 0

    function1()

    c.close
    conn.close()
    search_window.destroy()
    searchresult_window.lift()

def search_by_keyword():
    searchresult_window = Tk()
    searchresult_window.title('Program - Searchresult')

    #Checks the number of searchresults
    given_keyword = keyword.get()
    conn = sqlite3.connect('database.db')
    c = conn.cursor()
    c.execute("SELECT COUNT() FROM entry_table WHERE subject LIKE '%'||?||'%' OR header LIKE '%'||?||'%' OR entry LIKE '%'||?||'%'",
              (given_keyword, given_keyword, given_keyword))
    number = int(str(c.fetchone()).replace(",","").replace("(","").replace(")",""));

    #Gets data from database
    c.execute("SELECT * FROM entry_table WHERE subject LIKE '%'||?||'%' OR header LIKE '%'||?||'%' OR entry LIKE '%'||?||'%'",
              (given_keyword, given_keyword, given_keyword))
    data = c.fetchall()
    row_count = 0

    function1()

    c.close
    conn.close()
    search_window.destroy()
    searchresult_window.lift()

#Show all button
all_btn = Button(search_window, text="Show all entries", pady=5, bg='yellow1', command=search_all)
all_btn.grid(row=0, column=0)

#Search by keyword frame (including: entry field and search button)
search_by_keyword_frame = LabelFrame(search_window, text="Search by keyword", pady=5, bg='yellow1')
search_by_keyword_frame.grid(row=1, column=0)
keyword = Entry(search_by_keyword_frame)
keyword.delete(0, END)
keyword.i

nsert(END, str("Give Keyword"))
    keyword.grid(row=0, column=0)
    hae = Button(search_by_keyword_frame, text="SEARCH", pady=5, bg='yellow1', command=search_by_keyword)
    hae.grid(row=1, column=0)

    return_btn = Button(search_window, text="Return", pady=5, bg='yellow1', command =search_window.destroy)
    return_btn.grid(row=2, column=0, pady=5)


search_btn = Button(root, text="Search", pady=5, bg='yellow1', command=search)
search_btn.grid(row=2, column=0, pady=5)


root.mainloop()

Answer 1

This is your error output:

Exception in Tkinter callback Traceback (most recent call last): File "C:\Users\Name\AppData\Local\Programs\Python\Python38-32\lib\tkinter_init_.py", line 1883, in call return self.func(*args) File "C:/Users/Name/PycharmProjects/test/venv/Testi.py", line 49, in search_all function1() File "C:/Users/Name/PycharmProjects/test/Testi.py", line 14, in function1 main_frame = Frame(searchresult_window) NameError: name 'searchresult_window' is not defined

The root error the interpreter complain about is this bit:

line 14, in function1 main_frame = Frame(searchresult_window) NameError: name 'searchresult_window' is not defined

Meaning, Python interpreter can't find the variable searchresult_window to use it inside function1 because that is not in function1's scope. You have defined the variable inside some other function ( search_all ) and not passing it to function1. You should either pass the variable to function1 or define the variable in a scope where function1 has access to it. I defined the variable in the global scope, this should resolve the issue.

searchresult_window = Tk()
searchresult_window.title('Program - Searchresult')

def function1():
    # Scrollbar
    main_frame = Frame(searchresult_window)
    main_frame.pack(fill=BOTH, expand=1)
    my_canvas = Canvas(main_frame)
    my_canvas.pack(side=LEFT, fill=BOTH, expand=1)
    my_scroblbar = ttk.Scrollbar(main_frame, orient=VERTICAL, command=my_canvas.yview)
    my_scroblbar.pack(side=RIGHT, fill=Y)
    my_canvas.configure(yscrollcommand=my_scroblbar.set)
    my_canvas.bind('<Configure>', lambda e: my_canvas.configure(scrollregion=my_canvas.bbox("all")))
    seccond_frame = Frame(my_canvas)
    my_canvas.create_window((0, 0), window=seccond_frame, anchor="nw")

    # Displays searchresults on screen
    for _ in range(number):
        searchresult_frame = LabelFrame(seccond_frame, pady=5, bg='yellow1')
        searchresult_frame.pack()
        data_label = Label(hakutulos_frame, text=data[row_count][1], borderwidth=5, relief="groove", width=10)
        data_label.grid(row=0, column=0)

        row_count = row_count + 1

def search_all():    
    #Checks the number of searchresults
    conn = sqlite3.connect('database.db')
    c = conn.cursor()
    c.execute('SELECT COUNT() FROM entry_table')
    number = int(str(c.fetchone()).replace(",","").replace("(","").replace(")",""));

    #Gets data from database
    c.execute('SELECT * FROM entry_table')
    data = c.fetchall()
    row_count = 0

    function1()

    c.close
    conn.close()
    search_window.destroy()
    searchresult_window.lift()

Answer 2

Let's use your example / question and explain two options regarding Python.

The issue is that you create search_window inside the method search() so it is defined only there.

Python as a programming language gives you many alternatives (like any other programming language)

Option 1: use return

You can return the variable from the method and then use it in other location

def search():
    search_window = Toplevel(root)
    search_window.title('Program - Search')
    return search_window  # i added this line at the end of the function

later in the code you can do this:

    search_window = search()

Option 2: global keyword

Python gives you an ability to update (or define) global variables from inside a method.

def search():
    global search_window # added ths line to define global variable
    search_window = Toplevel(root)
    search_window.title('Program - Search')

Do not forget to call search() somewhere below (you don't do that in your example). From that point on, you will have a new variable named search_window. Simply approach it.