Morse Code Translator In Python

Morse code is a method of transmitting text information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment. It is named for Samuel F. B. Morse, an inventor of the telegraph.

Algorithm

The algorithm is very simple. Every character in the English language is substituted by a series of ‘dots’ and ‘dashes’ or sometimes just singular ‘dot’ or ‘dash’ and vice versa.

morse_img

Image Source : Wikipedia

Encryption

  1. In case of encryption we extract each character (if not a space) from a word one at a time and match it with its corresponding morse code stored in whichever data structure we have chosen(if you are coding in python, dictionaries can turn out to be very useful in this case)
  2. Store the morse code in a variable which will contain our encoded string and then we add a space to our string which will contain the result.
  3. While encoding in morse code we need to add 1 space between every character and 2 consecutive spaces between every word.
  4. If the character is a space then add another space to the variable containing the result. We repeat this process till we traverse the whole string

Decryption

  1. In case of decryption, we start by adding a space at the end of the string to be decoded (this will be explained later).
  2. Now we keep extracting characters from the string till we are not getting any space.
  3. As soon as we get a space we look up the corresponding English language character to the extracted sequence of characters (or our morse code) and add it to a variable which will store the result.
  4. Remember keeping track of the space is the most important part of this decryption process. As soon as we get 2 consecutive spaces we will add another space to our variable containing the decoded string.
  5. The last space at the end of the string will help us identify the last sequence of morse code characters (since a space acts as a check for extracting characters and start decoding them).

Implementation

Python provides a data structure called dictionary which stores information in the form of key-value pairs which is very convenient for implementing a cipher such as the morse code. We can save the morse code chart in a dictionary where (key-value pairs) => (English Characters-Morse Code). The plaintext (English characters) take the place of keys and the ciphertext (Morse code) form the values of the corresponding keys. The values of keys can be accessed from the dictionary in the same way we access the values of an array through their index and vice versa.

# Python program to implement Morse Code Translator

'''
VARIABLE KEY
'cipher' -> 'stores the morse translated form of the english string'
'decipher' -> 'stores the english translated form of the morse string'
'citext' -> 'stores morse code of a single character'
'i' -> 'keeps count of the spaces between morse characters'
'message' -> 'stores the string to be encoded or decoded'
'''

# Dictionary representing the morse code chart
MORSE_CODE_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':'--..',
                    '1':'.----', '2':'..---', '3':'...--',
                    '4':'....-', '5':'.....', '6':'-....',
                    '7':'--...', '8':'---..', '9':'----.',
                    '0':'-----', ', ':'--..--', '.':'.-.-.-',
                    '?':'..--..', '/':'-..-.', '-':'-....-',
                    '(':'-.--.', ')':'-.--.-'}

# Function to encrypt the string
# according to the morse code chart
def encrypt(message):
    cipher = ''
    for letter in message:
        if letter != ' ':

            # Looks up the dictionary and adds the
            # correspponding morse code
            # along with a space to separate
            # morse codes for different characters
            cipher += MORSE_CODE_DICT[letter] + ' '
        else:
            # 1 space indicates different characters
            # and 2 indicates different words
            cipher += ' '

    return cipher

# Function to decrypt the string
# from morse to english
def decrypt(message):

    # extra space added at the end to access the
    # last morse code
    message += ' '

    decipher = ''
    citext = ''
    for letter in message:

        # checks for space
        if (letter != ' '):

            # counter to keep track of space
            i = 0

            # storing morse code of a single character
            citext += letter

        # in case of space
        else:
            # if i = 1 that indicates a new character
            i += 1

            # if i = 2 that indicates a new word
            if i == 2 :

                 # adding space to separate words
                decipher += ' '
            else:

                # accessing the keys using their values (reverse of encryption)
                decipher += list(MORSE_CODE_DICT.keys())[list(MORSE_CODE_DICT
                .values()).index(citext)]
                citext = ''

    return decipher

# Hard-coded driver function to run the program
def main():
    message = "GEEKS-FOR-GEEKS"
    result = encrypt(message.upper())
    print (result)

    message = "--. . . -.- ... -....- ..-. --- .-. -....- --. . . -.- ... "
    result = decrypt(message)
    print (result)

# Executes the main function
if __name__ == '__main__':
    main()
Output:
--. . . -.- ... -....- ..-. --- .-. -....- --. . . -.- ... 
GEEKS-FOR-GEEKS

This article is contributed by Palash Nigam . If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

GATE CS Corner    Company Wise Coding Practice

Recommended Posts:







Writing code in comment? Please use ide.geeksforgeeks.org, generate link and share the link here.