X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=cipher.py;h=c4b28ba321ea4a55953af22f914c5b94a7843b6f;hb=be556d64f89152a697727a529947aff584fc0a54;hp=f938f3677f321d02805688ac443328314af0406f;hpb=e354c8aa351b8b9c0d9f28aa5708883c209809fe;p=cipher-tools.git

diff --git a/cipher.py b/cipher.py
index f938f36..c4b28ba 100644
--- a/cipher.py
+++ b/cipher.py
@@ -1,4 +1,5 @@
 import string
+import collections
 
 
 def caesar_cipher_letter(letter, shift):
@@ -21,3 +22,11 @@ def caesar_cipher_message(message, shift):
 
 def caesar_decipher_message(message, shift):
     return caesar_cipher_message(message, -shift)
+
+def letter_frequencies(message):
+    frequencies = collections.defaultdict(int)
+    for letter in message: 
+        if letter in  string.ascii_letters:
+            frequencies[letter.lower()]+=1
+    return frequencies
+