How to write a morse code translator in Python

Morse code is a communication system that uses a series of dots, dashes, and pauses to represent letters, numbers, and symbols. It was developed in the 1830s by Samuel Morse and Alfred Vail for the telegraph, which transmitted electrical signals over wires.

Morse code can be transmitted using sound, light, or electrical signals, and it is still used today in certain contexts, such as in aviation and amateur radio.

How it works

Each letter, number, and symbol represents a unique sequence of dots and dashes. For example, “A” is represented by a single dot followed by a dash $(.-)$, while “B” is represented by a dash followed by three dots $(-...)$.

The length of the dots and dashes and the pauses between them are standardized to send and receive messages efficiently and accurately.

Implementation in Python

We need to implement the following three core functionalities to make a Morse code translator in Python:

• Define a mapping of characters.

• Encode a message in Morse code.

• Decode a message from a Morse code sequence.

Define a mapping of characters

We define a dictionary that maps letters, numbers, and symbols to their respective Morse code sequences.

morse_dict = {
    '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': '--..', '0': '-----', '1': '.----', '2': '..---', '3': '...--', '4': '....-',
    '5': '.....', '6': '-....', '7': '--...', '8': '---..', '9': '----.', '.': '.-.-.-', ',': '--..--',
    '?': '..--..', "'": '.----.', '!': '-.-.--', '/': '-..-.', '(': '-.--.', ')': '-.--.-', '&': '.-...',
    ':': '---...', ';': '-.-.-.', '=': '-...-', '+': '.-.-.', '-': '-....-', '_': '..--.-', '"': '.-..-.',
    '$': '...-..-', '@': '.--.-.', ' ': '/'
}

The morse_dict dictionary has the following properties:

• A combination of the . and - characters denote different letters, numbers, and symbols.

• The / character denotes a separator between two words.

Encode a message in Morse code

We define a function that takes a message (a string) as input and returns the Morse code sequence for that message.

For example, the message Hello World will be converted to
.... . .-.. .-.. --- / .-- --- .-. .-.. -.. -.-.--.

Note: There is a space (" ") after each character and a forward slash (/) after each word in the Morse code sequence.

The to_morse_code function has the following properties:

• We initialize a variable, morse_code, with an empty string. This variable will store the Morse code sequence of the message.

• We convert the message into uppercase since Morse code is not case sensitive.

• We traverse each character of the capitalized message.

• We use each character as a key in the morse_dict dictionary to access the corresponding value (i.e., the Morse code representation of the character). Next, we add this value and a space character to the morse_code variable.

• After the message has been traversed, the morse_code variable contains the Morse code sequence of the message, so we return it.

Decode a message from a Morse code sequence

We define a function that takes a Morse code sequence (a string of dots, dashes, spaces, and slashes) as input and returns the corresponding message.

For example, the Morse code sequence .. / .- -- / .- / -... --- -.-- .-.-.- will be converted to I AM A BOY.

The from_morse_code function has the following properties:

• We initialize a variable, message, with an empty string. This variable will store the decoded message from the Morse code sequence.

• We reinitialize the morse_code variable by applying the split method on it with " " as the separator. This converts the Morse code sequence to a list containing the Morse code representation of each character as a separate element.

• We traverse the elements of the morse_code list.

• For each element, we traverse the morse_dict dictionary to find the key containing the character corresponding to its Morse code representation. We add this key to the message variable.

• After the list has been traversed, the message variable contains the decoded message, so we return it.

Putting it together

We implement a user interface that allows the user to choose whether to translate from text to Morse code or from Morse code to text.