🖼 人工智能学习总目录

🖼 《Python编程_从入门到实践》小结及目录

本章知识小结：

  • 1、f.read()、f.readlines()、f.write()
  • 2、words.split()
  • 3、try-except xxError-else
  • 4、import json、json.dump(numbers,f)、json.load(f)

1、读文件read()、逐行读readlines()

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filename = 'pi_million_digits.txt'

with open(filename) as file_object:
    #file = file_object.read()
    #for line in file[:3]:
    lines = file_object.readlines()

pi_string = ''
for line in lines:
    pi_string += line.strip()
    
birthday = input("Enter your birthday, in the form mmddyy: ")
if birthday in pi_string:
    print("Your birthday appears in the first million digits of pi!")
else:
    print("Your birthday does not appear in the first million digits of pi.")

2、写文件write()

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# write_message.py
filename = 'programming.txt'

with open(filename, 'a') as file_object:
    file_object.write("I also love finding meaning in large datasets.\n")
    file_object.write("I love creating apps that can run in a browser.\n")

3、try-except xxError-else

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# word_count.py
def count_words(filename):
    """Count the approximate number of words in a file."""
    try:
        with open(filename, encoding='utf-8') as f:
            contents = f.read()
    except FileNotFoundError:
        pass
    else:
        words = contents.split()
        num_words = len(words)
        print(f"The file {filename} has about {num_words} words.")

filenames = ['alice.txt', 'siddhartha.txt', 'moby_dick.txt', 'little_women.txt']
for filename in filenames:
    count_words(filename)

4、存储数据json.dump()、json.load()

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import json

numbers = [2, 3, 5, 7, 11, 13]

filename = 'numbers.json'
with open(filename, 'w') as f:
    json.dump(numbers, f)


filename = 'numbers.json'
with open(filename) as f:
    numbers = json.load(f)
    
print(numbers)

5、小结

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import json

# 是否有该用户
def get_stored_username():
    filename = 'username.json'
    try:
        with open(filename) as f:
            username = json.load(f)
    except FileNotFoundError:
        return None
    else:
        return username

# 创建新用户
def get_new_username():
    username = input("What is your name? ")
    filename = 'username.json'
    with open(filename, 'w') as f:
        json.dump(username, f)
    return username

# 欢迎用户
def greet_user():
    username = get_stored_username()
    if username:
        print(f"Welcome back, {username}!")
    else:
        username = get_new_username()
        print(f"We'll remember you when you come back, {username}!")

greet_user()