Files and I/O Examples
Key Takeaway: Practice Python with 110+ runnable examples covering strings, lists, dicts, math, dates, OOP, and file I/O — complete with expected terminal outputs.
Audience & Use Case: Designed for computer science students, data analysts, backend developers, and job seekers preparing for Python technical interviews.
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- Select a Python example topic from the sidebar menu (or mobile dropdown).
- Examine the structured source code and corresponding expected output.
- Copy code directly or test it in our Online Python Compiler.
- Experiment by tweaking variables, loops, and conditions to deepen your understanding.
Who is this for: Beginners, interview candidates, and developers looking for reliable code snippets.
Credible Resources:Python Tutorial · Python Compiler · Python 3 Official Documentation · JavaScript Examples
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])['a.txt', 'b.txt']
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())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())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')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())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)['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())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]).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'))c.txt
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()))3
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)True True
Python Program to Get the Full Path of the Current Working Directory
Uses os.getcwd.
import os print(os.getcwd() != '')
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'))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)}")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))
4.0
Python Core Concepts & Decision Breakdown
| Category | Core Concepts | Primary Use Case | Official Docs |
|---|---|---|---|
| Primitives & Basics | int, float, str, bool | Basic arithmetic, logic checks, string formatting | Built-in Types |
| Data Structures | list, tuple, dict, set | Collections, lookup maps, data filtering | Data Structures |
| Control Flow | if/else, for, while, try/except | Iteration, conditional execution, error handling | Control Flow |
| OOP & Modular | def, class, lambda, import | Object orientation, modularization, reusability | Classes & OOP |
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