P10-文件和异常

 

filename = 'pi_digits.txt'

with open(filename) as file_object:
    lines = file_object.readlines()

for line in lines:
    print(line.rstrip())

 

open() 接受的参数是当前目录下的文件名返回一个文件对象  然后用AS赋值给 file_object使用

关键字with 在不需要访问文件后将其关闭 这里没有调用close()方法,因为过早或者过晚的关闭都会出问题,

这里使用with可以让Python自己去判断什么时候去关闭而不需要我们去操作

使用read()获取文件内容或者readlines()获取每一行的内容

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")

 

r只读模式 w写入模式 a附加模式 r+读写模式  如果不加就按照默认的只读模式

print("Give me two numbers, and I'll divide them.")
print("Enter 'q' to quit.")

while True:
    first_number = input("\nFirst number: ")
    if first_number == 'q':
        break
    second_number = input("Second number: ")
    if second_number == 'q':
        break
    try:
        answer = int(first_number) / int(second_number)
    except ZeroDivisionError:
        print("You can't divide by 0!")
    else:
        print(answer)
print("Give me two numbers, and I'll divide them.")
print("Enter 'q' to quit.")

while True:
    first_number = input("\nFirst number: ")
    if first_number == 'q':
        break
    second_number = input("Second number: ")
    if second_number == 'q':
        break
    try:
        answer = int(first_number) / int(second_number)
    except ZeroDivisionError:
        print("You can't divide by 0!")
    else:
        print(answer)

 

 异常处理

try

except

else

pass  在except中 写 pass代表什么都不做的意思,但是提示后面的人可能做些什么

 

posted @ 2021-04-11 16:14  野兽Gentleman  阅读(79)  评论(0编辑  收藏  举报