StringWalker - Object-Oriented String Navigation

A Python class that provides an object-oriented way to walk through strings, get characters at specific positions, and replace characters.

Features

• String Navigation: Walk forward and backward through a string
• Character Access: Get characters at current position or specific positions
• Character Replacement: Replace characters at specific positions or current position
• Position Management: Move to specific positions, start, or end of string
• Bounds Checking: Safe navigation with bounds checking

Usage

Basic Usage

from string_walker import StringWalker

# Create a StringWalker with a string
walker = StringWalker("Hello, World!")

# Get current position and character
print(walker.get_current_position())  # 0
print(walker.get_current_character())  # 'H'

# Walk forward
walker.walk_forward(3)
print(walker.get_current_character())  # 'l'

# Walk backward
walker.walk_backward(1)
print(walker.get_current_character())  # 'e'

# Get character at specific position
char = walker.get_character_at(7)  # 'W'

# Replace character at position
walker.replace_character_at(7, 'X')
print(walker.get_string())  # "Hello, Xorld!"

Available Methods

Navigation Methods

• walk_forward(steps=1): Move forward by specified number of steps
• walk_backward(steps=1): Move backward by specified number of steps
• go_to_position(position): Move to a specific position
• go_to_start(): Move to the beginning of the string
• go_to_end(): Move to the end of the string

Character Access Methods

• get_current_character(): Get character at current position
• get_character_at(position): Get character at specific position
• get_current_position(): Get current position

Character Replacement Methods

• replace_character_at(position, new_char): Replace character at specific position
• replace_current_character(new_char): Replace character at current position

Utility Methods

• get_string(): Get the current string
• get_length(): Get the length of the string
• is_at_start(): Check if at the beginning
• is_at_end(): Check if at the end

Running the Demo

To see the StringWalker in action, run:

python3 string_walker.py

This will execute the demonstration code that shows all the features of the StringWalker class.

CLI Application

The StringWalker is also available as a command-line interface for interactive use:

Basic Usage

# Start with an initial string
python3 string_walker_cli.py "Hello World"

# Start without initial string (will prompt for one)
python3 string_walker_cli.py

# Run a quick demo
python3 string_walker_cli.py --demo

# Show help
python3 string_walker_cli.py --help

CLI Commands

Once in the interactive CLI, you can use these commands:

• help or h - Show help message
• status or s - Show current status
• forward <steps> or f <steps> - Walk forward (default: 1 step)
• backward <steps> or b <steps> - Walk backward (default: 1 step)
• goto <position> or g <pos> - Go to specific position
• start - Go to start of string
• end - Go to end of string
• get <position> - Get character at specific position
• replace <pos> <char> - Replace character at position
• current <char> - Replace character at current position
• string - Show the current string
• length - Show string length
• clear - Clear the screen
• quit, q, or exit - Exit the application

CLI Examples

walker> f 3                    # Walk forward 3 steps
walker> b                      # Walk backward 1 step
walker> g 5                    # Go to position 5
walker> get 7                  # Get character at position 7
walker> replace 3 X            # Replace character at position 3 with 'X'
walker> current Y              # Replace current character with 'Y'

Running Tests

To run comprehensive tests and examples, use:

python3 test_examples.py

This will run various test scenarios including:

• Basic operations
• Navigation methods
• Character replacement
• Bounds checking
• Edge cases (empty strings, single characters)

Interactive Demo

The test_examples.py file also includes an interactive demo. To use it, uncomment the last line in the file and run:

python3 test_examples.py

This will allow you to interactively walk through any string you provide.

Example Output

=== StringWalker Demo ===
Initial string: 'Hello, World!'
Length: 13
Current position: 0
Current character: 'H'

Walking forward 3 steps...
Position: 3, Character: 'l'

Walking backward 1 step...
Position: 2, Character: 'l'

Getting character at position 7...
Character at position 7: 'W'

Replacing character at position 7 with 'X'...
Updated string: 'Hello, Xorld!'

Going to position 10...
Position: 10, Character: 'd'

Replacing current character with 'Y'...
Updated string: 'Hello, XorlY!'

Going to start...
Position: 0, Character: 'H'

Going to end...
Position: 12, Character: '!'

=== Final State ===
StringWalker at position 12 (char: '!') of 'Hello, XorlY!'

Error Handling

The StringWalker class includes bounds checking:

• Navigation methods return True if successful, False if out of bounds
• Character access methods return None if the position is out of bounds
• Replacement methods return False if the position is out of bounds or the new character is invalid