英文:
Delete text using file operators in python
问题
你可以使用以下代码将文件 "example.pdf" 中第一个 "Hello" 之后的内容删除：
with open("example.pdf", "r+") as file:
data = file.read()
index = data.find("Hello")
if index != -1:
file.seek(index)
file.truncate()
这段代码将文件 "example.pdf" 中第一个 "Hello" 之后的内容截断，使其被删除。
英文:
Say there is a code:
with open("example.pdf", "r") as file:
String = file.seek(-11, os.SEEK_END)
print(String)
and the output is Hello Hello
How would you change the text in the file "example.pdf" so that everything after the first Hello is deleted using file operators(read/write/append)?
Thank you for your help!!
答案1
得分: 2
打开文件以适当的模式。确定要截断文件的偏移量。调用truncate()并关闭文件。
例如（对于普通文本文件）：
import os
def remove_after(filename, text):
with open(filename, 'r+') as f:
contents = f.read()
offset = contents.find(text)
if offset >= 0:
pos = offset + len(text)
f.seek(pos, os.SEEK_SET)
f.truncate()
remove_after('/Volumes/G-Drive/foo.txt', 'hello')
对于二进制文件，模式应为'rb+'，确定截断点的机制可能会有所不同。
请注意，从二进制文件中删除任意内容可能会破坏其内部结构，具体取决于文件的内容。
英文:
Open the file in the appropriate mode. Determine the offset where you want to truncate the file. Call truncate() and close the file.
For example (for a plain text file):
import os
def remove_after(filename, text):
with open(filename, 'r+') as f:
contents = f.read()
offset = contents.find(text)
if offset >= 0:
pos = offset + len(text)
f.seek(pos, os.SEEK_SET)
f.truncate()
remove_after('/Volumes/G-Drive/foo.txt', 'hello')
For a binary file the mode should be rb+ and the mechanism for determining the truncation point is likely to be different.
Bear in mind though that deleting arbitrary content from a binary file may break its internal structure depending on what the file is
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