Python读取文件比open快十倍的库fileinput

# demo.py
import fileinput

for line in fileinput.input():
    print(line) 

$ python demo.py 
hello
hello

python
python

import fileinput

with fileinput.input(files=('a.txt',)) as file:
    for line in file:
        print(f'{fileinput.filename()} 第{fileinput.lineno()}行: {line}', end='') 

$ python demo.py
a.txt 第1行: hello
a.txt 第2行: world

import fileinput

with fileinput.input(files=('a.txt', 'b.txt')) as file:
    for line in file:
        print(f'{fileinput.filename()} 第{fileinput.lineno()}行: {line}', end='') 

$ cat a.txt
hello
world
$ cat b.txt
hello
python

$ python demo.py
a.txt 第1行: hello
a.txt 第2行: world
b.txt 第3行: hello
b.txt 第4行: python

import fileinput

with fileinput.input(files=('a.txt', 'b.txt')) as file:
    for line in file:
        print(f'{fileinput.filename()} 第{fileinput.filelineno()}行: {line}', end='') 

$ python demo.py
a.txt 第1行: hello
a.txt 第2行: world
b.txt 第1行: hello
b.txt 第2行: python

import fileinput
import glob
 
for line in fileinput.input(glob.glob("*.txt")):
    if fileinput.isfirstline():
        print('-'*20, f'Reading {fileinput.filename()}...', '-'*20)
    print(str(fileinput.lineno()) + ': ' + line.upper(), end="")

$ python demo.py
-------------------- Reading b.txt... --------------------
1: HELLO
2: PYTHON
-------------------- Reading a.txt... --------------------
3: HELLO
4: WORLD

import fileinput
with fileinput.input(files=("a.txt",), backup=".bak") as file:
    for line in file:
        print(f'{fileinput.filename()} 第{fileinput.lineno()}行: {line}', end='') 

$ ls -l a.txt*
-rw-r--r--  1 MING  staff  12  2 27 10:43 a.txt

$ python demo.py
a.txt 第1行: hello
a.txt 第2行: world

$ ls -l a.txt*
-rw-r--r--  1 MING  staff  12  2 27 10:43 a.txt
-rw-r--r--  1 MING  staff  42  2 27 10:39 a.txt.bak

import fileinput

with fileinput.input(files=("a.txt",), inplace=True) as file:
    print("[INFO] task is started...") 
    for line in file:
        print(f'{fileinput.filename()} 第{fileinput.lineno()}行: {line}', end='') 
    print("[INFO] task is closed...") 

$ cat a.txt
hello
world

$ python demo.py
[INFO] task is started...
[INFO] task is closed...

$ cat a.txt 
a.txt 第1行: hello
a.txt 第2行: world

import sys
import fileinput

for line in fileinput.input(files=('a.txt', ), inplace=True):
    #将windows/DOS格式下的文本文件转为linux的文件
    if line[-2:] == "\r\n":  
        line = line + "\n"
    sys.stdout.write(line)

def online_open(url, mode):
    import requests
    r = requests.get(url) 
    filename = url.split("/")[-1]
    with open(filename,'w') as f1:
        f1.write(r.content.decode("utf-8"))
    f2 = open(filename,'r')
    return f2

import fileinput

file_url = 'https://www.csdn.net/robots.txt'
with fileinput.input(files=(file_url,), openhook=online_open) as file:
    for line in file:
        print(line, end="")

User-agent: * 
Disallow: /scripts 
Disallow: /public 
Disallow: /CSS/ 
Disallow: /images/ 
Disallow: /content/ 
Disallow: /ui/ 
Disallow: /js/ 
Disallow: /scripts/ 
Disallow: /article_preview.html* 
Disallow: /tag/
Disallow: /*?*
Disallow: /link/

Sitemap: Https://www.csdn.net/sitemap-aggpage-index.xml
Sitemap: https://www.csdn.net/article/sitemap.txt 

import fileinput
for line in fileinput.input('data.txt'):
  print(line, end="")

import fileinput
import glob
 
for line in fileinput.input(glob.glob("*.txt")):
    if fileinput.isfirstline():
        print('-'*20, f'Reading {fileinput.filename()}...', '-'*20)
    print(str(fileinput.lineno()) + ': ' + line.upper(), end="")

import sys
import fileinput

for line in fileinput.input(files=('a.txt', ), inplace=True):
    #将Windows/DOS格式下的文本文件转为Linux的文件
    if line[-2:] == "\r\n":  
        line = line + "\n"
    sys.stdout.write(line)

#--样本文件--：error.log
aaa
1970-01-01 13:45:30  Error: **** Due to System Disk spacke not enough...
bbb
1970-01-02 10:20:30  Error: **** Due to System Out of Memory...
ccc
 
#---测试脚本---
import re
import fileinput
import sys
 
pattern = '\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}'
 
for line in fileinput.input('error.log',backup='.bak',inplace=1):
    if re.search(pattern,line):
        sys.stdout.write("=> ")
        sys.stdout.write(line)
 
#---测试结果---
=> 1970-01-01 13:45:30  Error: **** Due to System Disk spacke not enough...
=> 1970-01-02 10:20:30  Error: **** Due to System Out of Memory...

import sys
import re
import fileinput
 
pattern= re.compile(sys.argv[1])
for line in fileinput.input(sys.argv[2]):
    if pattern.match(line):
        print(fileinput.filename(), fileinput.filelineno(), line)
$ ./test.py import.*re *.py
#查找所有py文件中，含import re字样的
addressBook.py  2   import re
addressBook1.py 10  import re
addressBook2.py 18  import re
test.py         238 import re