请求协助完成交换单词中间右侧字母与末尾字母的Python程序

Hey there! Let's walk through finishing this Python program to meet all your requirements, and fix the small issues in your existing code along the way.

First: Add Input Validation #

The first thing we need to do is make sure the user enters a word with at least 3 characters. A simple while loop will handle this—we'll keep asking for input until they give us something valid:

# Loop until we get a valid input (3+ characters)
while True:
    word = input('Please enter a word with a minimum of 3 characters: ')
    word_length = len(word)
    if word_length >= 3:
        break
    print('Oops! That word is too short. Please try again.')

Fix the Middle Index & Print Statement #

Your original code had a syntax error in the print line (you forgot to close a quote, and were printing the text word[word_middle_index] instead of the actual character). Let's fix that, and confirm we're targeting the correct middle-right character:

# Calculate the middle-right index (works for even/odd lengths)
word_middle_index = word_length // 2
# Print the middle-right character correctly
print(f'The middle-right letter of "{word}" is: {word[word_middle_index]}')

Quick examples:

• For "switch" (6 characters), 6//2 = 3 → we grab the 4th character (index 3) which is 't'
• For "apple" (5 characters), 5//2 = 2 → we grab the 3rd character (index 2) which is 'p'

Implement the Letter Swap #

Since Python strings are immutable (we can't change characters directly), we'll convert the word to a list, swap the middle-right character with the last character, then convert it back to a string:

# Convert word to a list so we can modify characters
word_list = list(word)
# Swap middle-right character with the last character
word_list[word_middle_index], word_list[-1] = word_list[-1], word_list[word_middle_index]
# Turn the list back into a string
modified_word = ''.join(word_list)

Full Working Code #

Putting all these pieces together, here's the complete program:

# Get valid input with minimum 3 characters
while True:
    word = input('Please enter a word with a minimum of 3 characters: ')
    word_length = len(word)
    if word_length >= 3:
        break
    print('Oops! That word is too short. Please try again.')

# Calculate middle-right index and display the character
word_middle_index = word_length // 2
print(f'The middle-right letter of "{word}" is: {word[word_middle_index]}')

# Perform the swap operation
word_list = list(word)
word_list[word_middle_index], word_list[-1] = word_list[-1], word_list[word_middle_index]
modified_word = ''.join(word_list)

# Show the final result
print(f'\nOriginal word: {word}')
print(f'Modified word: {modified_word}')

Example Run #

Here's what it looks like when you run the program:

Please enter a word with a minimum of 3 characters: hi
Oops! That word is too short. Please try again.
Please enter a word with a minimum of 3 characters: switch
The middle-right letter of "switch" is: t

Original word: switch
Modified word: swihct

内容的提问来源于stack exchange，提问作者Veronica