Swap argv for argparse, Fixed #1 More robust help, code cleanup.

Caeser-Cipher/caeser-cipher.py

@@ -1,22 +1,20 @@
-# Python Caeser Cipher Helper v1.1.0
+# Python Caeser Cipher Helper v1.2.0
 # Usage (encrypt): python3 caeser-cipher.py encrypt secretmessage
 # Usage (decrypt): python3 caeser-cipher.py decrypt secretmessage
 
 import re # Import Regex tools
 import string # Import string tools
 import collections # Import tools to sort letters.
-from sys import argv # Import tool to process command line arguments.
+import argparse
 
-#if action == "help": # If error, print help https://stackoverflow.com/questions/4042452/display-help-message-with-python-argparse-when-script-is-called-without-any-argu
-    #print("\nUsage (encrypt): python3 caeser-cipher.py encrypt secretmessage")
-    #print("Usage (decrypt): python3 caeser-cipher.py decrypt secretmessage\n")
+parser = argparse.ArgumentParser(usage="(encrypt): python3 caeser-cipher.py encrypt [secretmessage] [shift]\nusage: (decrypt): python3 caeser-cipher.py decrypt [secretmessage] [shift]\nusage: If you don't know the shift of encrypted text, use 0\nusage: For example: python3 caeser-cipher.py decrypt hhhhh 0")
+parser.add_argument("action")
+parser.add_argument("ciphertext")
+parser.add_argument("shiftNum")
+args = parser.parse_args()
 
-script, action, ciphertext = argv # Take command line input.
-
-#ciphertext = input("Please type in your cipher text:") # Set variable cipertext to the input from user.
-shiftNum = input("Please enter the shift you would like to use (Just hit enter if you don't know the shift used):") # Get input
-#action = input("Please enter encrypt or decrypt):") # Get input
-ciphertext = re.sub (r'([^a-zA-Z]+?)', '', ciphertext) # Remove all non-letters.
+shiftNum = args.shiftNum
+ciphertext = re.sub (r'([^a-zA-Z]+?)', '', args.ciphertext) # Remove all non-letters.
 ciphertext = ciphertext.lower() # Make it all lowercase. https://www.geeksforgeeks.org/isupper-islower-lower-upper-python-applications/
 letters = list(string.ascii_lowercase) # Use a list of lowercase letters. https://stackoverflow.com/questions/43918437/how-to-iterate-through-the-alphabet
 
@@ -51,7 +49,7 @@ def encrypt(ciphertext, shiftNum, letters): # Grab parameters
     print("\nYour enciphered text is: " + answer)
 
 
-def decrypt(ciphertext, shiftNum, letters, commonletter): # Grab parameters
+def decrypt(ciphertext, shiftNum, letters): # Grab parameters
 
     # Create local variables for this function.
 
@@ -105,13 +103,13 @@ def freq(ciphertext):
 
             letterPos = letterPos + 1 # Iterate through letter positions in the alphabet. (neccessary to find one that matches.)
 
-    decrypt(ciphertext, shiftNum, letters, commonletter) # Decrypt using the frequency found in here.
+    decrypt(ciphertext, shiftNum, letters) # Decrypt using the frequency found in here.
 
 
-if action == "encrypt":
+if args.action == "encrypt":
     encrypt(ciphertext, shiftNum, letters) # Start the encrypt() function while passing 3 variables as parameters.
-if action == "decrypt":
-    if shiftNum == "":
+if args.action == "decrypt":
+    if shiftNum == "0":
         freq(ciphertext)
     else:
-        decrypt(ciphertext, shiftNum, letters, commonletter)
+        decrypt(ciphertext, shiftNum, letters)