如何在 Python 中逐个字符地删除 Tkinter StringVar？

Question

I am new to Python and learning Tkinter now. I am working on a simple calculator and need to define a function for the Erase button in my project to delete the entered number character by character (not just cleaning the entry at once).

Answer 1

You can overwrite your existing string with a string containing all characters except the last one:

Example with a Tkinter StringVar:

import tkinter as tk

root = tk.Tk()
text = tk.StringVar()
text.set('Hello world')
text.set(text.get()[0:-1]) # Hello worl (the "d" was removed)
tk.Label(root, textvariable=text).grid()
root.mainloop()

Example with a simple Python string:

text = "Hello world"
text = text[0:len(text)-1]
print(text) # Hello worl (the "d" was removed)

The method len(text) returns the length of the string, then we read from the first character ( 0 ) up to the penultimate one ( len(text)-1] ) and overwrite the existing string.

As @jasonharper has pointed out, you can replace text[0:len(text)-1] with text[0:-1] , which looks cleaner and has the same practical effect.