Exercise 20 from LPTHW Book

Wednesday, January 31 2024 2159

Author: dodofold

ex20.py

@@ -0,0 +1,33 @@
+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("\nNow 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
+print_a_line(current_line, current_file)
+
+current_line = current_line + 1
+print_a_line(current_line, current_file)

test.txt

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