add trigraphcount

vignere.py

@@ -45,10 +45,37 @@ def decrypt(string,key):
         resultstring = resultstring+chr(c+97)
     print(resultstring)
 
+def trigraphcount(string):
+    distances = {}
+    for i in range(0,len(string)-2):
+        trigraph = string[i:i+3]
+        index = 0
+        while index < len(string):
+            index = string.find(trigraph, index)
+            if index == -1:
+                break
+            print(trigraph+' found at', index)
+            if not trigraph in distances and index!=i:
+                distances[trigraph] = index - i
+            index += 3
+    #print(distances)
+    print(sorted(distances.items(), key=lambda x: x[1]))
+
+def lettercount(string,dist):
+    letters = {}
+    for i in range(0,len(string)-dist,dist):
+        print(string[i:i+dist])
+        for c in string:
+            if c in letters:
+                letters[c] = letters[c]+1
+            else:
+                letters[c] = 1
+    print(letters)
+
 def main(argv):
     key = ""
     try:
-        opts, args = getopt.getopt(argv,"hk:e:d:",["key=","encrypt=","decrypt="])
+        opts, args = getopt.getopt(argv,"hk:e:d:t:l:",["key=","encrypt=","decrypt=","trigraphs=","lettercount="])
     except getopt.GetoptError:
         print(os.path.basename(__file__)+' -k <key> -e <plain text>')
         print(os.path.basename(__file__)+' -k <key> -d <encrypted text>')
@@ -64,5 +91,9 @@ def main(argv):
             encrypt(arg,key)
         elif opt in ("-d", "--decrypt"):
             decrypt(arg,key)
+        elif opt in ("-t", "--trigraphs"):
+            trigraphcount(arg)
+        elif opt in ("-l", "--lettercount"):
+            lettercount(arg,int(key))
 if __name__ == '__main__':
     main(sys.argv[1:])