完成第十章文件和异常练习

Author: OctopusLian

chapter10/10-1.py

@@ -0,0 +1,23 @@
+# encoding: utf-8
+
+filename = 'learning_python.txt'
+
+# 第一次打印读取整个文件
+print("--- Reading in the entire file:")
+with open(filename) as f:
+    contents = f.read()
+print(contents)
+
+# 第二次打印时遍历文件对象
+print("\n--- Looping over the lines:")
+with open(filename) as f:
+    for line in f:
+        print(line.rstrip())
+
+# 第三次打印时将各行存储在一个列表中，再在with代码块外打印它们
+print("\n--- Storing the lines in a list:")
+with open(filename) as f:
+    lines = f.readlines()
+
+for line in lines:
+    print(line.rstrip())

chapter10/10-11-read.py

@@ -0,0 +1,6 @@
+import json
+
+with open('favorite_number.json') as f:
+    number = json.load(f)
+
+print("I know your favorite number! It's " + str(number) + ".")

chapter10/10-11-write.py

@@ -0,0 +1,7 @@
+import json
+
+number = input("What's your favorite number? ")
+
+with open('favorite_number.json', 'w') as f:
+    json.dump(number, f)
+    print("Thanks! I'll remember that.")

chapter10/10-12.py

@@ -0,0 +1,12 @@
+import json
+
+try:
+    with open('favorite_number.json') as f:
+        number = json.load(f)
+except FileNotFoundError:
+    number = input("What's your favorite number? ")
+    with open('favorite_number.json', 'w') as f:
+        json.dump(number, f)
+    print("Thanks, I'll remember that.")
+else:
+    print("I know your favorite number! It's " + str(number) + ".")

chapter10/10-13.py

@@ -0,0 +1,36 @@
+import json
+
+def get_stored_username():
+    """Get stored username if available."""
+    filename = 'username.json'
+    try:
+        with open(filename) as f_obj:
+            username = json.load(f_obj)
+    except FileNotFoundError:
+        return None
+    else:
+        return username
+
+def get_new_username():
+    """Prompt for a new username."""
+    username = input("What is your name? ")
+    filename = 'username.json'
+    with open(filename, 'w') as f_obj:
+        json.dump(username, f_obj)
+    return username
+
+def greet_user():
+    """Greet the user by name."""
+    username = get_stored_username()
+    if username:
+        correct = input("Are you " + username + "? (y/n) ")
+        if correct == 'y':
+            print("Welcome back, " + username + "!")
+        else:
+            username = get_new_username()
+            print("We'll remember you when you come back, " + username + "!")
+    else:
+        username = get_new_username()
+        print("We'll remember you when you come back, " + username + "!")
+
+greet_user()

chapter10/10-2.py

@@ -0,0 +1,10 @@
+# encoding: utf-8
+
+filename = './learning_python.txt'
+
+with open(filename) as f:
+    lines = f.readlines()
+
+for line in lines:
+    line = line.rstrip()
+    print(line.replace('Python', 'C'))

chapter10/10-3.py

@@ -0,0 +1,6 @@
+name = input("What's your name? ")
+
+filename = 'guest.txt'
+
+with open(filename, 'w') as f:
+    f.write(name)

chapter10/10-4.py

@@ -0,0 +1,11 @@
+filename = 'guest_book.txt'
+
+print("Enter 'quit' when you are finished.")
+while True:
+    name = input("\nWhat's your name? ")
+    if name == 'quit':
+        break
+    else:
+        with open(filename, 'a') as f:
+            f.write(name + "\n")
+        print("Hi " + name + ", you've been added to the guest book.")

chapter10/10-5.py

@@ -0,0 +1,14 @@
+filename = 'programming_poll.txt'
+
+responses = []
+while True:
+    response = input("\nWhy do you like programming? ")
+    responses.append(response)
+
+    continue_poll = input("Would you like to let someone else respond? (y/n) ")
+    if continue_poll != 'y':
+        break
+
+with open(filename, 'a') as f:
+    for response in responses:
+        f.write(response + "\n")

chapter10/10-6.py

@@ -0,0 +1,13 @@
+try:
+    x = input("Give me a number: ")
+    x = int(x)
+
+    y = input("Give me another number: ")
+    y = int(y)
+
+except ValueError:
+    print("Sorry, I really needed a number.")
+
+else:
+    sum = x + y
+    print("The sum of " + str(x) + " and " + str(y) + " is " + str(sum) + ".")