Files and I/O Examples
Read and write files, inspect paths, list directory contents, and compute file hashes. These examples cover real-world tasks you’ll use in automation scripts and everyday data processing.
Python Program to Get Line Count of a File
Counts lines.
open('c.txt','w').write('x\ny\nz')
print(len(open('c.txt').read().splitlines()))
Output
3
Python File I/O
Write and read text from a file.
with open("out.txt", "w") as f:
f.write("Hello file\n")
with open("out.txt", "r") as f:
print(f.readline().strip())
Output
Hello file
Python Program to Find Hash of File
Computes MD5 of file.
import hashlib
with open('tmp.txt','w') as f: f.write('data')
m = hashlib.md5()
with open('tmp.txt','rb') as f:
for chunk in iter(lambda: f.read(8192), b''):
m.update(chunk)
print(m.hexdigest())
Output
8d777f385d3dfec8815d20f7496026dc
Python Program to Safely Create a Nested Directory
Creates directories if missing.
from pathlib import Path
Path('nested/dir/path').mkdir(parents=True, exist_ok=True)
print('ok')
Output
ok
Python Program to Copy a File
Uses shutil.copyfile.
import shutil
open('a.txt','w').write('hello')
shutil.copyfile('a.txt','b.txt')
print(open('b.txt').read())
Output
hello
Python Program Read a File Line by Line Into a List
Reads lines into list.
open('lines.txt','w').write('a\nb\nc')
with open('lines.txt') as f:
lines = [line.strip() for line in f]
print(lines)
Output
['a', 'b', 'c']
Python Program to Append to a File
Appends content.
open('append.txt','w').write('start\n')
with open('append.txt','a') as f:
f.write('more\n')
print(open('append.txt').read().strip())
Output
start more
Python Program to Extract Extension From the File Name
Uses os.path.splitext.
import os
print(os.path.splitext('archive.tar.gz')[1])
Output
.gz
Python Program to Get the File Name From the File Path
Uses os.path.basename.
import os
print(os.path.basename('/a/b/c.txt'))
Output
c.txt
Python Program to Find All File with .txt Extension Present Inside a Directory
Uses glob.
import glob
open('d1.txt','w').close()
open('d2.txt','w').close()
print(sorted(glob.glob('*.txt'))[:2])
Output
['a.txt', 'b.txt']
Python Program to Get File Creation and Modification Date
Uses os.path.*time.
import os, time
open('time.txt','w').close()
print(os.path.getctime('time.txt') > 0)
print(os.path.getmtime('time.txt') > 0)
Output
True True
Python Program to Get the Full Path of the Current Working Directory
Uses os.getcwd.
import os print(os.getcwd() != '')
Output
True
Python Program to Check the File Size
Uses os.path.getsize.
open('size.txt','w').write('12345')
import os
print(os.path.getsize('size.txt'))
Output
5
Python Strings Basics
Concatenate, format, and slice strings.
s = "Hello, Python"
print(s.lower())
print(s.upper())
print(s[0:5])
print(f"Length: {len(s)}")
Output
hello, python HELLO, PYTHON Hello Length: 13
Python Program to Find the Square Root
Computes square root using math module.
import math print(math.sqrt(16))
Output
4.0
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