使用 - 运算符操作学校作业文件[已关闭]

Question

大家好，我有一个文本文档，其中有两组数字 4-1 和 9-3 代码需要读取它们并写入同一个文本文档中，并且需要注意换行符，然后代码需要计算它们并打印而不需要输入 tnx 寻求帮助

我已经尝试过了

f = open("Odin.txt","r")
print(f.read())
f.close()


f = open("Odin.txt","w")

for f in line:
    res = eval(line.strip())
    output.write(line.strip()+"="+str(res)+"\n")
f.close()

f = open("Odin.txt","r")
print(f.readline(),end="")
print(f.readline(),end="")
f.close()

Answer 1

你的选项1很接近，但你的

for f in line

是向后的；你想要

for line in f

（即迭代

line

ile 中的每个

f

）。如果您在开始写出修改后的版本之前阅读整个文件，也会更容易。

# Read a copy of the file into memory as a list.
with open("Odin.txt") as f:
    lines = list(map(str.strip, f.readlines()))

# Write out the new content.
with open("Odin.txt", "w") as f:
    for line in lines:
        f.write(f"{line}={eval(line)}\n")

>cat Odin.txt
4-1
9-3

>python odin.py
>cat Odin.txt
4-1=3
9-3=6

Answer 2

import re

output = ""

with open("New Text Document.txt", "r") as file:
    # This gets the expression before the "=" and removes all the leading and trailing whitespaces
    text = [(re.sub("=(.*)", "", line)).strip() for line in file.readlines()]

    for line in text:
        try:
            output += f"{line} = {eval(line)}\n"
        except SyntaxError:
            pass

with open("New Text Document.txt", "w") as file:
    file.write(output)

所以基本上先阅读文档，然后将我想要在文件中写入的所有内容放入变量中。然后我只需在写入模式下再次打开它并写入我的输出即可。