Question

Please write a Python program to

1. Ask user to input a string from keyboard. The string must contain at least a '\', a space, a lower-case letter, an upper-case letter, and a number. If the input string does not satisfy the rule, ask the user to re-input.
2. Print the obtained string.
3. Replace all the '\' by 'n' in the obtained string.

Answer 1

def get_valid_input():
while True:
user_input = input("Enter a string containing at least '\\' a space, a lowercase letter, an uppercase letter, and a number: ")
if '\\' in user_input and ' ' in user_input and any(char.islower() for char in user_input) and any(char.isupper() for char in user_input) and any(char.isdigit() for char in user_input):
return user_input
else:
print("Invalid input. Please re-enter the string.")

def replace_backslash(input_str):
modified_str = input_str.replace('\\', 'n')
return modified_str

# Step 1: Get a valid input string
valid_input_string = get_valid_input()

# Step 2: Print the obtained string
print("Obtained String:", valid_input_string)

# Step 3: Replace all '\' with 'n' and print the modified string
modified_string = replace_backslash(valid_input_string)
print("Modified String:", modified_string)

Answer 2

Below is a Python program that prompts the user to input a string meeting specific criteria, prints the obtained string, and then replaces all backslashes (`\`) with the character 'n' in the obtained string:

```python

while True:

user_input = input("Enter a string with '\\' , space, lower-case and upper-case letters, and a number: ")

if all(c in user_input for c in ['\\', ' ', 'a', 'A', '1']):

break

print(f"Obtained String: {user_input}")

modified_string = user_input.replace('\\', 'n')

print(f"Modified String: {modified_string}")

```

Step-by-step explanation:

The Python program begins by using a `while` loop to continually prompt the user for input until the provided string meets the specified criteria, including the presence of a backslash, a space, a lower-case letter, an upper-case letter, and a number. The `all` function is employed to check if all the required characters are present in the user input.

Once a valid string is obtained, the program prints the original string. Subsequently, the program utilizes the `replace` method to replace all occurrences of backslashes in the obtained string with the character 'n'. The modified string is then printed to the console.

This program ensures that the user provides a string meeting the specified conditions and demonstrates string manipulation using Python's built-in methods. The inclusion of a `while` loop guarantees that the user input is validated before proceeding with further actions, enhancing the robustness of the program.