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课程简介

Python for Everybody 零基础程序设计（Python 入门）

• This course aims to teach everyone the basics of programming computers using Python. 本课程旨在向所有人传授使用 Python 进行计算机编程的基础知识。
• We cover the basics of how one constructs a program from a series of simple instructions in Python. 我们介绍了如何通过 Python 中的一系列简单指令构建程序的基础知识。
• The course has no pre-requisites and avoids all but the simplest mathematics. Anyone with moderate computer experience should be able to master the materials in this course. 该课程没有任何先决条件，除了最简单的数学之外，避免了所有内容。任何具有中等计算机经验的人都应该能够掌握本课程中的材料。
• This course will cover Chapters 1-5 of the textbook “Python for Everybody”. Once a student completes this course, they will be ready to take more advanced programming courses. 本课程将涵盖《Python for Everyday》教科书的第 1-5 章。学生完成本课程后，他们将准备好学习更高级的编程课程。
• This course covers Python 3.

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coursera

Python for Everybody 零基础程序设计（Python 入门）

Charles Russell Severance
Clinical Professor

个人主页
Twitter

University of Michigan

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课程资源

coursera原版课程视频
coursera原版视频-中英文精校字幕-B站
Dr. Chuck官方翻录版视频-机器翻译字幕-B站

PY4E-课程配套练习
Dr. Chuck Online - 系列课程开源官网

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Quiz 5: Loops and Iterations

We look at how Python repeats statements using looping structures.

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单选题（1-10）

1. What is wrong with this Python loop:

n = 5
while n > 0 :
    print(n)
print('All done')

• This loop will run forever
• while is not a Python reserved word
• The print(‘All done’) statement should be indented four spaces
• There should be no colon on the while statement

2. What does the break statement do?

• Resets the iteration variable to its initial value
• Jumps to the “top” of the loop and starts the next iteration
• Exits the currently executing loop
• Exits the program

3. What does the continue statement do?

• Resets the iteration variable to its initial value
• Jumps to the “top” of the loop and starts the next iteration
• Exits the currently executing loop
• Exits the program

4. What does the following Python program print out?

tot = 0
for i in [5, 4, 3, 2, 1] :
    tot = tot + 1
print(tot)

• 10
• 5
• 15
• 0

5. What is the iteration variable in the following Python code:

friends = ['Joseph', 'Glenn', 'Sally']
for friend in friends :
     print('Happy New Year:',  friend)
print('Done!')

• Joseph
• friend
• Glenn
• Sally

6. What is a good description of the following bit of Python code?

zork = 0
for thing in [9, 41, 12, 3, 74, 15] :
    zork = zork + thing
print('After', zork)

• Count all of the elements in a list
• Find the smallest item in a list
• Compute the average of the elements in a list
• Sum all the elements of a list

7. What will the following code print out?

smallest_so_far = -1
for the_num in [9, 41, 12, 3, 74, 15] :
   if the_num < smallest_so_far :
      smallest_so_far = the_num
print(smallest_so_far)

Hint: This is a trick question and most would say this code has a bug - so read carefully

• 74
• -1
• 3
• 42

8. What is a good statement to describe the is operator as used in the following if statement:

if smallest is None :
     smallest = value

• matches both type and value
• Is true if the smallest variable has a value of -1
• Looks up ‘None’ in the smallest variable if it is a string
• The if statement is a syntax error

9. Which reserved word indicates the start of an “indefinite” loop in Python?

• break
• while
• def
• for
• indef

10. How many times will the body of the following loop be executed?

n = 0
while n > 0 :
    print('Lather')
    print('Rinse')
print('Dry off!')

• 0
• 1
• 5
• This is an infinite loop

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编程题

Exercise 5.2

题目：
Write a program that repeatedly prompts a user for integer numbers until the user enters ‘done’.
Once ‘done’ is entered, print out the largest and smallest of the numbers.
If the user enters anything other than a valid number catch it with a try/except and put out an appropriate message and ignore the number.
Enter 7, 2, bob, 10, and 4 and match the output below.

[Desired Output]
Invalid input
Maximum is 10
Minimum is 2

解题代码：

largest = None
smallest = None

while True:
   num = input("Enter a number: ")
   
   if num == "done":
       break
   try:        
       n = int(num)
   except:
       print("Invalid input")
       continue
   else:
       if largest is None:
           largest = n
       elif largest < n:
           largest = n
           
       if smallest is None:
           smallest = n
       elif smallest > n:
           smallest = n

print("Maximum", "is", largest)
print("Minimum", "is", smallest)