文件与错误

文件

读取

with open("pi_digits.txt")as file_object:##file_object写什么都可以，记住就行
    contents = file_object.read()
print(contents)

# 逐行读取
with open("pi_digits.txt") as file_object:
    for line in file_object:#line的空行与Print的空行
        print(line)

#取消空行
with open("pi_digits.txt") as file_object:
    for line in file_object:
        print(line.rstrip())

file_name = "pi_digits.txt"

with open(file_name) as file_object:
    lines = file_object.readlines()
#包含文件内容的列表
for line in lines:
    print(line.rstrip())

pi_string = ""
for line in lines:
    pi_string += line.rstrip()
print(pi_string)

pi_string = ""
for line in lines:
    pi_string += line.strip()
print(pi_string)

pi = float(pi_string)
print(pi * 2)

with open("pi_million_digits.txt") as file_object:
    lines = file_object.readlines()

pi_string = ""
for line in lines:
    pi_string += line.strip()
print(pi_string[:52])

birthday = input("Enter your birthday, int 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!")

结果

3.1415926535 
  8979323846 
  2643383279

3.1415926535 

  8979323846 

  2643383279

3.1415926535
  8979323846
  2643383279
3.1415926535
  8979323846
  2643383279
3.1415926535  8979323846  2643383279
3.141592653589793238462643383279
6.283185307179586
3.14159265358979323846264338327950288419716939937510
Enter your birthday, int the form mmddyy121400
Your birthday appears in the first million digits of pi!

写入

filename = "programming.txt"

with open(filename, "w") as file_object:
    file_object.write("I love programming.\n")#python只能写入字符串
    file_object.write("I love creating new games.\n")

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

json

import json

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

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

import json

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

print(numbers)

错误

处理错误以防崩溃

filename = "alice.txt"


def count_words(filename):
    try:
        with open(filename, encoding="utf-8") as f:
            contents = f.read()
    except FileNotFoundError:
        # print(f"Sorry, the file {filename} does not exist.")
        pass#静默失败，'pass'表示什么也不做，同时充当占位符
    else:
        words = contents.split()
        num_words = len(words)
        print(f"The file {filename} has about {num_words} words.")

filenames = ["alice.txt", "FILE NOT EXIST.txt","siddhartha.txt", "moby_dick.txt", "little_women.txt"]
for filename in filenames:
    count_words(filename)

在项目中新加的玩意
main.py

def import_info(filename: str) -> list:
    try:
        with open(filename) as f:
            info = json.load(f)
            dragons = []
    except FileNotFoundError:#其实没有好多用，文件内容可能不正确，等等
        print(f"{filename} not found")
        exit()
    else:
        for key in info:
            dragons.append(dragon.Dragon(key[0], key[1], key[2], key[3], key[4], key[5]))
        return dragons

while True:
    try:
        self.player_choice(int(input()), key)
    except ValueError:
        print("Please check your input")
    else:
        break

重构

你经常会遇到这样的情况：代码能够正确地运行，但通过将其划分为一系列完成具体工作的函数，还可以改进。这样的过程称为重构 。重构让代码更清晰、更易于理解、更容易扩展。

学习后面的项目时就会发现重构的重要性，比如在重构函数的基础上重构