added another solution

PythonCHB · Anastomose · commit 1fa519b4a71d · 2014-10-28T18:35:07.000-07:00
diff --git a/Solutions/Session04/copy_file.py b/Solutions/Session04/copy_file.py
@@ -8,8 +8,8 @@
 
 source, dest = sys.argv[1:3]
 
-infile = open(source, 'rb')
-outfile = open(dest, 'wb')
+infile = open(source, 'rb') # read binary mode
+outfile = open(dest, 'wb')  # write binary mode
 
 outfile.write(infile.read())
 infile.close()
diff --git a/Solutions/Session04/safe_input.py b/Solutions/Session04/safe_input.py
@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+
+"""
+Exceptions Lab solution:
+
+The raw_input() function can generate two exceptions:
+EOFError or KeyboardInterrupt on end-of-file(EOF) or canceled input.
+
+Create a wrapper function, perhaps safe_input() that returns None rather
+rather than raising these exceptions, when the user enters ^C for Keyboard
+Interrupt, or ^D (^Z on Windows) for End Of File.
+
+NOTE: if the user types a few charactors, and the hits ctrl+C, the
+KeyboardInterrupt gets caught somewhere deeper in the process, and
+this function doesn't work.
+
+Don't worry about that -- I do'nt really understnd what's going on in
+the REPL (Read, Evaluate, Print Loop) either -- and the point of this
+assigment is simple Exception handling.
+"""
+
+
+def safe_input(prompt_string=""):
+    """
+    print user for input -- returning a raw string.
+
+    This is just like the built-in raw_input(), but it will return None
+    if the user hits ctrl+c, ratehr than raise an Exception.
+    """
+    try:
+        response = raw_input(prompt_string)
+        return response
+    except (EOFError, KeyboardInterrupt):
+        return None
+
+if __name__ == "__main__":
+    response = safe_input("Say Something: ")
+    print "You said:", response
+
+
+
diff --git a/slides_sources/source/session04.rst b/slides_sources/source/session04.rst
@@ -893,11 +893,13 @@ Nope: the *type* is the problem::
 
 but should you be checking type anyway? (EAFP)
 
+===
 LAB
-====
+===
 
 Exceptions Lab
 
+
 Exceptions Lab
 ---------------
 
@@ -1198,15 +1200,15 @@ In the class repo, in:
 
 ``Examples\Session01\students.txt``
 
-You will find the list I genrated of all the students in teh class, and
-what programming langues they used in the past.
+You will find the list I generated of all the students in the class, and
+what programming languages they have used in the past.
 
 Write a little script that reads that file, and generates a list of all
 the languages that have been used.
 
-Extra credit: keep track of how many sutdents specified each language.
+Extra credit: keep track of how many students specified each language.
 
-If you've got giot set up right, ``git pull upstream master`` should update
+If you've got git set up right, ``git pull upstream master`` should update
 your repo. Otherwise, you can get it from gitHub:
 
 ``https://github.com/UWPCE-PythonCert/IntroToPython/blob/master/Examples/Session01/students.txt``
