[Python #3] create e20.py

kjg/python-the-hard-way/e20.py

@@ -0,0 +1,35 @@
+from sys import argv
+
+script, input_file = argv
+
+def print_all(f):
+    print(f.read())
+
+def rewind(f):
+    f.seek(0)
+
+def print_a_line(line_count, f):
+    print(line_count, f.readline())
+
+current_file = open(input_file)
+
+print("First let's print the whole file: \n")
+
+print_all(current_file)
+
+print("Now let's rewind, kind of like a tape.")
+
+rewind(current_file)
+
+print("Let's print three lines:")
+
+current_line = 1
+print_a_line(current_line, current_file)
+
+#current_line = current_line + 1
+current_line += 1
+print_a_line(current_line, current_file)
+
+#current_line = current_line + 1
+current_line += 1
+print_a_line(current_line, current_file)

kjg/python-the-hard-way/test.txt

@@ -1 +1,3 @@
-This is a test file.
+This is line 1
+This is line 2
+This is line 3

kjg/python.org

@@ -92,3 +92,5 @@ How to copy file
 How to use function
 **** ex19
 How to use function and variables
+**** ex20
+How to use function with file