pandas 如何通过网络驱动器从 .csv 文件中快速获取最后一行？
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How to quickly get the last line from a .csv file over a network drive?
提问by user1367204
I store thousands of time series in .csvfiles on a network drive. Before I update the files, I first get the last line of the file to see the timestamp and then I update with data after that timestamp. How can I quickly get the last line of a .csvfile over a network drive so that I don't have to load the entire huge .csvfile only to use the last line?
我.csv在网络驱动器上的文件中存储了数千个时间序列。在更新文件之前，我首先获取文件的最后一行以查看时间戳，然后使用该时间戳之后的数据进行更新。如何.csv通过网络驱动器快速获取文件的最后一行，这样我就不必加载整个大.csv文件才能使用最后一行？
回答by Douglas
There is a nifty reversedtool for this, assuming you are using the built-in csvmodule:
reversed假设您正在使用内置csv模块，则有一个漂亮的工具：
how to read a csv file in reverse order in python
In short:
简而言之：
import csv
with open('some_file.csv', 'r') as f:
for row in reversed(list(csv.reader(f))):
print(', '.join(row))
In my test file of:
在我的测试文件中：
1: test, 1
2: test, 2
3: test, 3
This outputs:
这输出：
test, 3
test, 2
test, 1
