From 991779bc672bb25bc290cf55a03e8a13bb51f294 Mon Sep 17 00:00:00 2001
From: kjg <jinguk.kwon@ungleich.ch>
Date: Fri, 22 May 2020 22:49:51 +0900
Subject: [PATCH] [Python #3] create e20.py

---
 kjg/python-the-hard-way/e20.py   | 35 ++++++++++++++++++++++++++++++++
 kjg/python-the-hard-way/test.txt |  4 +++-
 kjg/python.org                   |  2 ++
 3 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 kjg/python-the-hard-way/e20.py

diff --git a/kjg/python-the-hard-way/e20.py b/kjg/python-the-hard-way/e20.py
new file mode 100644
index 0000000..8f7cee7
--- /dev/null
+++ b/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)
diff --git a/kjg/python-the-hard-way/test.txt b/kjg/python-the-hard-way/test.txt
index 6de7b8c..e97bf0c 100644
--- a/kjg/python-the-hard-way/test.txt
+++ b/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
diff --git a/kjg/python.org b/kjg/python.org
index 57a1a0d..aa4fc79 100644
--- a/kjg/python.org
+++ b/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