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Question

我的文本文档有两组数字 4-1 和 9-3 代码需要读取它们并在同一个文本文档中写入并且需要注意换行符然后需要计算它们并打印而不输入作为选项 2 tnx 全部求助

我尝试了选项 1

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()

我尝试选项 2

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

f = open("Odin.txt","w")
a = 4-1
b = 9-3
f.write(f"4-1 = {a}\n")
f.write(f"9-3 = {b}\n")
f.close()

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

Answer 1

我可能会这样做：

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，然后将我想在文件中写入的所有内容放在一个变量中。然后我只需以写入模式再次打开它并写入我的输出。

Answer 2

您的选项 1 很接近，但您的 for f in line 倒退了；你想要for line in f（即遍历file 中的每个line）。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