Finished for the day

[cipher-training.git] / slides / caesar-encipher.html

diff --git a/slides/caesar-encipher.html b/slides/caesar-encipher.html
index c4e8fb10f4d01ebff0b8e4d249e3599df61e4f93..f45a166ca80d71f37605364c4dac44c9e43925d1 100644 (file)
--- a/slides/caesar-encipher.html
+++ b/slides/caesar-encipher.html
@@ -120,6 +120,49 @@ if __name__ == "__main__":
 
 ---
 
+# Accents
+
+```python
+>>> caesar_encipher_letter('é', 1)
+```
+What does it produce?
+
+What should it produce?
+
+## Unicode, combining codepoints, and normal forms
+
+Text encodings will bite you when you least expect it.
+
+* urlencoding is the other pain point.
+
+---
+
+# Five minutes on StackOverflow later...
+
+```python
+def unaccent(text):
+    """Remove all accents from letters. 
+    It does this by converting the unicode string to decomposed compatibility
+    form, dropping all the combining accents, then re-encoding the bytes.
+
+    >>> unaccent('hello')
+    'hello'
+    >>> unaccent('HELLO')
+    'HELLO'
+    >>> unaccent('héllo')
+    'hello'
+    >>> unaccent('héllö')
+    'hello'
+    >>> unaccent('HÉLLÖ')
+    'HELLO'
+    """
+    return unicodedata.normalize('NFKD', text).\
+        encode('ascii', 'ignore').\
+        decode('utf-8')
+```
+
+---
+
 # Doing all the letters
 
 ## Test-first developement
@@ -186,7 +229,7 @@ ciphertext = [caesar_encipher_letter(p, key) for p in plaintext]
     <script src="http://gnab.github.io/remark/downloads/remark-0.6.0.min.js" type="text/javascript">
     </script>
     <script type="text/javascript">
-      var slideshow = remark.create();
+      var slideshow = remark.create({ ratio: "16:9" });
     </script>
   </body>
 </html>
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