如何在Python中读取大文件的特定部分 [英] How to read specific part of large file in Python

问题描述

给出一个大文件(数百MB)，我将如何使用Python快速读取文件中特定起始索引和结束索引之间的内容?

Given a large file (hundreds of MB) how would I use Python to quickly read the content between a specific start and end index within the file?

本质上，我正在寻找一种更有效的方法:

Essentially, I'm looking for a more efficient way of doing:

open(filename).read()[start_index:end_index]

推荐答案

您可以将文件seek放入文件，然后从那里读取一定数量. Seek允许您获取文件内的特定偏移量，然后可以将读取限制为该范围内的字节数.

You can seek into the file the file and then read a certain amount from there. Seek allows you to get to a specific offset within a file, and then you can limit your read to only the number of bytes in that range.

with open(filename) as fin:
    fin.seek(start_index)
    data = fin.read(end_index - start_index)

那只会读取您要查找的数据.

That will only read that data that you're looking for.

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