从列表框和列表中删除选定的项目

Question

我有一个用 C# 编写的应用程序需要转换为 Python，因为我最近切换到了 Linux。这是一个简单的 GUI 应用程序，用于在学习新语言的同时管理未知单词。不过，我需要 remove_item() 函数，我还需要 find_word() 函数。

在 C# 中，我将创建以下两个方法：

void Remove()
{
    Word word = new Word();
    try { word = FindWord(listView1.SelectedItems[0].Text); }
    catch { return; }
    if (listView1.SelectedItems.Count > 0)
    {
        try
        {
            foreach (ListViewItem eachItem in listView1.SelectedItems)
            {
                words.RemoveAll(x => x.WordOrPhrase == eachItem.Text);
                listView1.Items[listView1.Items.Count - 1].Selected = true;
                listView1.Items.Remove(eachItem);
            }
        }
        catch { }
        ClearAll();
        ReadOnlyON();
    }
    else
    {
        MessageBox.Show("You have not selected any words!", "Notification", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
    ReadOnlyOFF();
    WordCount();
    Sync();
}

private Word FindWord(string word)
{
    return words.Find(x => x.WordOrPhrase == word);
}

...但是在 Python 方面我仍然是新手，因此我们将不胜感激。这是我目前所拥有的：

对于 FindWord() 方法，可以改写如下：

def FindWord(word):
    for x in words:
        if x.WordOrPhrase == word:
            return x

或

def FindWord(word):
    return next((x for x in words if x.WordOrPhrase == word), None)

或

def FindWord(word):
    return next(filter(lambda x: x.WordOrPhrase == word, words), None)

...但我正在努力重写 Remove() 方法。这是一种方法：

def remove_item(self):
    word = self.listBox.get(ACTIVE)
    new_word_list = []  # initialize empty list
    delete_idxs = []
    for idx, item in enumerate(self.words):
        if item.wordorphrase == word:
            delete_idxs.append(idx)
        else:
            new_word_list.append(item)
    self.words = new_word_list  # overwrite the old word_list with the new one
    for idx in reversed(delete_idxs):
        self.listBox.delete(idx)

...我最想要的是将我的 C# 方法转换为 Python。这是我目前所拥有的：

def remove_item(self):

    word = Word()

    try:
        word = find_word(self.listBox.curselection())
    except:
        return

    if self.listBox.len(curselection()) > 0:
        try:
            for item in self.listBox.curselection():
                self.words.remove(lambda x: x.wordorphrase == item.text)
                # listView1.Items[listView1.Items.Count - 1].Selected = true;
                self.listBox.remove(item)
        except:
            pass
        self.clear_all()

    else:
        pass
        # show messagebox

我不知道如何访问：

• listView1.SelectedItems[0].Text
• listView1.SelectedItems.Count > 0
• listView1.SelectedItems
• listView1.Items[listView1.Items.Count - 1].Selected

这是我到目前为止所做的：

# Vocabulary.py
# GUI program to manage unknown words

from tkinter import *
from tkinter import ttk
from tkinter import messagebox
import xml.etree.ElementTree as ET
import os


class Word:

    def __init__(self, wordorphrase, explanation, translation, example):
        self.wordorphrase = wordorphrase
        self.explanation = explanation
        self.example = example
        self.translation = translation

class Vocabulary(Frame):

    def __init__(self, master):
        Frame.__init__(self, master)
        self.master = master
        self.master.resizable(width = False, height = False)
        self.master.title("Vocabulary")
        self.create_widgets()
        self.words = []
        self.load_words()

    def on_closing(self):

        self.save_all()

        if messagebox.askokcancel("Quit", "Do you want to quit?"):
            self.master.destroy()

    def create_widgets(self):

        self.buttons_frame = Frame(self.master)
        self.buttons_frame.grid(row = 10, sticky = W)

        self.search_frame = Frame(self.master)
        self.search_frame.grid(row = 1, sticky = W, columnspan = 2)

        self.comboBox = ttk.Combobox(self.search_frame,
                                     width = 3)
        self.comboBox.grid(row = 0, column = 14, sticky = W)
        self.comboBox['values'] = ( 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' )

        self.btn_Add = Button(self.buttons_frame,
                              text = 'Add',
                              command = self.add_item)
        self.btn_Add.grid(row = 0, sticky = W)

        self.btn_Remove = Button(self.buttons_frame,
                                 text = 'Remove',
                                 command = self.remove_item)

        self.btn_Remove.grid(row = 0, column = 1, sticky = W)

        self.btn_Edit = Button(self.buttons_frame,
                               text = 'Edit',
                               command = self.edit_item)
        self.btn_Edit.grid(row = 0, column = 2, sticky = W)

        self.btn_Save = Button(self.buttons_frame,
                               text = 'Save',
                               command = self.save_item)
        self.btn_Save.grid(row = 0, column = 3, sticky = W)

        self.btn_Refresh = Button(self.buttons_frame,
                                  text = 'Refresh',
                                  command = self.refresh_all)
        self.btn_Refresh.grid(row = 0, column = 4, sticky = W)

        self.lblSearch = Label(self.search_frame, text = 'SEARCH: ')
        self.lblSearch.grid(row = 0, column = 5, sticky = W)

        self.txt_Search = Text(self.search_frame,
                               height = 1,
                               width = 70)
        self.txt_Search.grid(row = 0, column = 6, columnspan = 3, sticky = W)

        self.lblWordsOrPhrases = Label(self.master, text = 'WORDS/PHRASES:')
        self.lblWordsOrPhrases.grid(row = 2, column = 0)

        self.lblWordOrPhrase = Label(self.master, text = 'Word or phrase:')
        self.lblWordOrPhrase.grid(row = 2, column = 1, sticky = W)

        self.listBox = Listbox(self.master,
                               selectmode='extended',
                               height = 34,
                               width = 38)
        self.listBox.grid(row = 3, column = 0, rowspan = 7, sticky = W)

        self.txt_WordOrPhrase = Text(self.master,
                                     height = 1,
                                     width = 40)
        self.txt_WordOrPhrase.grid(row = 3, column = 1, sticky = N)

        self.lblExplanation = Label(self.master, text = 'Explanation:')
        self.lblExplanation.grid(row = 4, column = 1, sticky = W)

        self.txt_Explanation = Text(self.master,
                                    height = 10,
                                    width = 40)
        self.txt_Explanation.grid(row = 5, column = 1, sticky = N)

        self.lblTranslation = Label(self.master, text = 'Translation:')
        self.lblTranslation.grid(row = 6, column = 1, sticky = W)

        self.txt_Translation = Text(self.master,
                                    height = 10,
                                    width = 40)
        self.txt_Translation.grid(row = 7, column = 1, sticky = N)

        self.lblExamples = Label(self.master, text = 'Example(s):')
        self.lblExamples.grid(row = 8, column = 1, sticky = W)

        self.txt_Example = Text(self.master,
                                height = 10,
                                width = 40)
        self.txt_Example.grid(row = 9, column = 1, sticky = S)

    def load_words(self):

        self.listBox.delete(0, END)
        self.words.clear()

        path = os.path.expanduser('~/Desktop')
        vocabulary = os.path.join(path, 'Vocabulary', 'Words.xml')

        if not os.path.exists(vocabulary):
            if not os.path.exists(os.path.dirname(vocabulary)):
                os.mkdir(os.path.dirname(vocabulary))
            doc = ET.Element('Words')
            tree = ET.ElementTree(doc)
            tree.write(vocabulary)
        else:
            tree = ET.ElementTree(file=vocabulary)

        for node in tree.findall('WordOrPhrase'):
            w = Word(node.find('Word').text, node.find('Explanation').text, node.find('Translation').text,
                     node.find('Examples').text)

            self.words.append(w)
            self.listBox.insert(END, w.wordorphrase)

    def save_all(self):

        path = os.path.expanduser('~/Desktop')
        vocabulary = os.path.join(path, 'Vocabulary', 'Words.xml')

        tree = ET.ElementTree(file=vocabulary)

        for xNode in tree.getroot().findall('WordOrPhrase'):
            tree.getroot().remove(xNode)

        for w in self.words:
            xTop = ET.Element('WordOrPhrase')
            xWord = ET.Element('Word')
            xExplanation = ET.Element('Explanation')
            xTranslation = ET.Element('Translation')
            xExamples = ET.Element('Examples')

            xWord.text = w.wordorphrase
            xExplanation.text = w.explanation
            xTranslation.text = w.translation
            xExamples.text = w.example

            xTop.append(xWord)
            xTop.append(xExplanation)
            xTop.append(xTranslation)
            xTop.append(xExamples)

            tree.getroot().append(xTop)

        tree.write(vocabulary)

    def add_item(self):

        w = Word(self.get_word(), self.get_explanation(), self.get_translation(), self.get_example())

        self.words.append(w)

        self.listBox.insert(END, w.wordorphrase)

        self.clear_all()

        self.save_all()

    def remove_item(self):

        word = Word()

        try:
            word = find_word(self.listBox.curselection())
        except:
            return

        if self.listBox.len(curselection()) > 0:
            try:
                for item in self.listBox.curselection():
                    self.words.remove(lambda x: x.wordorphrase == item.text)
                    # listView1.Items[listView1.Items.Count - 1].Selected = true;
                    self.listBox.remove(item)
            except:
                pass
            self.clear_all()

        else:
            pass
            # show messagebox

    def edit_item(self):
        pass

    def save_item(self):
        pass

    def clear_all(self):
        self.txt_WordOrPhrase.delete('1.0', END)
        self.txt_Explanation.delete('1.0', END)
        self.txt_Translation.delete('1.0', END)
        self.txt_Example.delete('1.0', END)

    def refresh_all(self):
        pass

    def get_word(self):
        return self.txt_WordOrPhrase.get('1.0', '1.0 lineend')

    def get_explanation(self):
        return self.txt_Explanation.get('1.0', '1.0 lineend')

    def get_translation(self):
        return self.txt_Translation.get('1.0', '1.0 lineend')

    def get_example(self):
        return self.txt_Example.get('1.0', '1.0 lineend')

    def find_word(word):
        for x in self.words:
            if x.wordorphrase == word:
                return x


def main():
    root = Tk()
    gui = Vocabulary(root)
    root.protocol('WM_DELETE_WINDOW', gui.on_closing)
    root.mainloop()

if __name__ == '__main__':
    main()

Answer 1

对于我的列表框，我通常将模式设置为EXTENDED，以便用户可以选择一个或多个项目并一次删除所有项目。我通过以下方法这样做：

# Function with Tk.Listbox passed as arg
def remove_from(list_box):

    # Tuple of currently selected items in arg
    selected_items = list_box.curselection()

    # Initialize a 'repositioning' variable
    pos = 0

    for item in selected_items:
        # Set index of each item selected
        idx = int(item) - pos
        # Deletes only that index in the listbox
        list_box.delete(idx, idx)
        # Increments to account for shifts
        pos += 1

例如，假设在我的列表框中我有 4 个项目。然后我选择第一项和第三项。通过致电list_box.curselection()，我收到了以下信息：

selected_items = (0, 2)

其中0 是列表框中第一项的位置，2 是第三项的位置。然后对于我的元组中的每个项目，我建立它的索引。

遍历此，对于第一项，发生以下情况：

idx = 0 - 0
list_box.delete(0, 0)
pos = 1

所以现在我删除了位置0 的项目（例如第一个项目）并且我的列表框已经移动！所以第二个现在是第一个，第三个是第二个，第四个是第三个。但是，我的元组 没有改变，因为它是 original 选择的列表框中的位置。这是关键。接下来发生的事情是：

idx = 2 - 1
list_box.delete(1, 1)
pos = 2

由于列表框移动，位置1 现在对应于最初位于列表框第三位置的项目。对于n 职位，这可以继续。

用于删除 self.words

您可以尝试以下方法：

# Function with Tk.Listbox and self.words[] passed as args
def remove_from(list_box, list):

    # Tuple of currently selected items in arg
    selected_items = list_box.curselection()

    # List of Words already constructed
    word_list = list

    # Initialize a 'repositioning' variable
    pos = 0

    for item in selected_items:
        # Set index of each item selected
        idx = int(item) - pos
        # Deletes only that index in the listbox
        list_box.delete(idx, idx)
        # Gets the string value of the given index
        word = list_box.get(idx, idx)
        # Removes the word from the list
        if any(word in x for x in word_list):
            word_list.remove(word)
        # Increments to account for shifts
        pos += 1