Python Caesar Cipher Decoder

Question

In my lesson I was tasked with creating a Caesar Cipher decoder that takes a string of input and finds the best possible string using a letter frequencies. If not sure how m

Answer 1

I'm working on the same tutorial and used a slightly different method. This avoided creating and calling functions:

inp = input()     #to hold code text
code = list(inp)  #store code as a list
soln = []         #store the 'Goodness' for each of 26 possible answers
y=0               #variable to hold total goodness during calculations
clear = []        #will hold decoded text
pos=0             #position marker for a list

#for every possible value of shift
#note range as 0 to 25 are valid shifts and shift 26 = shift 0

for shift in range(0,26):
   for i in code:                  #loop through each letter in code
      if i == " ":                 #spaces have no score so omit them
         continue
      else:                        #if it's a letter
         x = ord(i)-shift          #apply the test shift
         if x < 65:                #prevent shifting outside A-Z range
            x = x + 26             
         x = x - 64                #turn ord into character position in A-Z with A=1
         x = letterGoodness[x-1]   #turn this into the Goodness score
         y = y + x                 #add this to a running total
   soln.insert(shift-1,y)          #AFTER decoding all letters in code, add total(y) to list of scores
   y = 0                           #reset y before next test value

bestSoln=max(soln)                 #find highest possible score

for i in range(0,26):              #check the list of solutions for this score
   if soln[i]==bestSoln:           #the position in this list is the shift we need
       bestShift = i+1             #+1 as the first solution is 0

for i in code:                     #now decode the original text using our best solution
   if i == " ":                    #spaces are not encoded so just add these to the string
      clear.insert(pos," ")        #pos used to track next position for final string
      pos = pos + 1
      continue
   else:
      x = ord(i)-bestShift         #same operation as before
      if x < 65:
         x = x + 26
   z = chr(x)
   clear.insert(pos,z)             #add the decoded letter to the clear text
   pos = pos + 1
print("".join(clear))              #join the list of clear text into one string and print it

Note that many parts of this code could (and should) be compressed, for example

x = x - 64
x = letterGoodness[x-1]
y = y + x

They are left expanded to 'show my working' for a tutorial exercise.