使用python读取文本文件并按扩展名排序

Question

I would like to read a text file using python. If a line with .cpp found, process it first and then if a line with .java extension found, process it second .

Test.py is my sample code, using a for loop, it will read Test.txt and then it will process COMPILE_JAVA() method first and then it will execute COMPILE_CPP() method.

Test.txt

/home/jenkins/workspace/a/Hello.java
/home/jenkins/workspace/b/Hello.cpp
/home/jenkins/workspace/b/Hello1.cpp

Test.py

for f in files:
    ACTION1 = False
    ACTION2 = False
    with open(f, 'r') as file:
        for line in (file):
            if ACTION1 is False and ('.cpp' in line ):
                COMPILE_CPP()
                ACTION1 = True
            elif ACTION2 is False and '.java' in line:
                COMPILE_JAVA()
                ACTION2 = True
                break

Answer 1

IIUC you can sort the list you read from test.txt by extension using os.path.splitext :

import os

with open(f, 'r') as file:
    sorted_files = sorted(file, key=lambda x: os.path.splitext(x)[1])
    for line in sorted_files:
        # rest of the code

Given

l = ['/home/jenkins/workspace/a/Hello.java',
     '/home/jenkins/workspace/b/Hello.cpp',
     '/home/jenkins/workspace/b/Hello1.cpp']

Then running sorted(l, key=lambda x: os.path.splitext(x)[1]) returns:

['/home/jenkins/workspace/b/Hello.cpp',
 '/home/jenkins/workspace/b/Hello1.cpp',
 '/home/jenkins/workspace/a/Hello.java']

Explanation:

os.path.splitext returns a tuple (root, ext), eg os.path.splitext("dir/myfile.txt") returns ("dir/myfile", ".txt") , so lambda x: os.path.splitext(x)[1] returns the second part ( .txt ).

This is then passed as an argument to the sorted function, so the list gets sorted alphabetically by extension.

Answer 2

Maybe this can help? I used bubble sort to sort the extensions.

row_list = []
with open("test.txt", "r") as file:
    line = file.readline()
    while line:
        row_list.append(line)

for i in range(1, len(row_list)):
    for j in range(len(row_list), i, -1):
        ext1 = row_list[j-1].split(".")[1]
        ext2 = row_list[j].split(".")[1]
        if ext1 > ext2:
            row_list[j-1], row_list[j] = row_list[j], row_list[j-1]

with open("output_file.txt", "w") as file:
    for row in row_list:
        file.write(f"{row}\n")