How to read the last line of a file in Python?

Question

I have a two requirements .

First Requirement-I want to read the last line of a file and assign the last value to a variable in python.

Second Requirement-

Here is my sample file.

<serviceNameame="demo" wsdlUrl="demo.wsdl" serviceName="demo"/> <context:property-placeholder location="filename.txt"/> 

From this file I want to read the content i.e filename.txt which will be after <context:property-placeholder location= ..And want to assign that value to a variable in python.

Answer 1

A simple solution, which doesn't require storing the entire file in memory (e.g with file.readlines() or an equivalent construct):

with open('filename.txt') as f:     for line in f:         pass     last_line = line 

For large files it would be more efficient to seek to the end of the file, and move backwards to find a newline, e.g.:

import os  with open('filename.txt', 'rb') as f:     try:  # catch OSError in case of a one line file          f.seek(-2, os.SEEK_END)         while f.read(1) != b'\n':             f.seek(-2, os.SEEK_CUR)     except OSError:         f.seek(0)     last_line = f.readline().decode() 

Note that the file has to be opened in binary mode, otherwise, it will be impossible to seek from the end.