Skip to content

Snippets

_is_it_worth_the_time.png

File Path

Get the current file, path, fullpath

import sys, os
print('sys.argv[0] =', sys.argv[0])             
print('path =', os.path.dirname(sys.argv[0]))
print('full path =', os.path.abspath(os.path.dirname(sys.argv[0])))

Web

  • Webserver on Python 2: python -m SimpleHTTPServer 8008
  • Webserver on Python 3: python -m http.server 8008 --bind 127.0.0.1

String manipulation

  • Convert Binary to String: b'a string'.decode('ascii')
  • Convet String to Integer: int(string)
  • Convert Int to String: str(integer)
  • Remove Duplicates from a List: L = list(set(L))
  • Input space separated integers in a list: lis = list(map(int, input().split()))
  • Get Integers from a String (space separated): ints = [int(x) for x in S.split()]
  • Swap two numbers a and b: a, b = b, a

Functions

  • Finding Factorial: fac=lambda(n):reduce(int.__mul__,range(1,n+1),1) or print(math.factorial(n))
  • Get even numbers: evenNumbers =[x for x in range(11) if x % 2 == 0]
  • Finding all subsets of a set: print(list(combinations([1, 2, 3, 4, 5, 6], 3)))

  • Finding greatest common divisor:

    def gcd(a,b):
    while(b):a,b=b,a%b
        return a

  • lambda function example using square root:

    sqr = lambda x: x * x
print(sqr(5))

Create a random string

randomstring.py
import random
import string

def getpassword(pwlength, extrachars):
    password = []
    for i in range(pwlength):
        password.append(random.choice(string.ascii_letters + string.digits + string.punctuation + extrachars))
    return "".join(password)

print("English password: " + getpassword(22, ""))
print("German password:  " + getpassword(22, "äöüßÄÖÜẞ"))
print("Italian password: " + getpassword(22, "ÀÈÉÌÒÙàèéìòù"))
print("French password:  " + getpassword(22, "ÀÂÄÆÇÈÉÊËÎÏÔŒÙÛÜàâäæçrèéêëîïôœùûü"))
print("Spanish password: " + getpassword(22, "¡¿ÁÉÍÑÓÚÜáéíñóúü"))

  • Execute Shell Commands

    execute-shell-command.py
    import subprocess
cmd = subprocess.Popen(
['ls', '-l', '.'],
cwd='/',
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT
)
stdout, stderr = cmd.communicate()
print(stdout)
print(stderr)

Network

HTTP JSON request

HTTP-JSON-request.py
import json, urllib.request

req = urllib.request.Request("https://example.com")
req.add_header("Accept", "application/json")

try:
    r = urllib.request.urlopen(req)
    data = json.loads(r.read())
    print(json.dumps(data))
except urllib.error.HTTPError as e:
    print(e.code)
    print(e.read())

HTTP Plain request

HTTP-Plain-request.py
import urllib.request

req = urllib.request.Request("https://example.com")

try:
    r = urllib.request.urlopen(req)
    data = r.read().decode("utf-8")
    print(data)
except urllib.error.HTTPError as e:
    print(e.code)
    print(e.read())

Colors

Print some colors

colors.py
class colors:
reset='\033[0m'
bold='\033[01m'
disable='\033[02m'
underline='\033[04m'
reverse='\033[07m'
strikethrough='\033[09m'
invisible='\033[08m'
class fg:
black='\033[30m'
red='\033[31m'
green='\033[32m'
orange='\033[33m'
blue='\033[34m'
purple='\033[35m'
cyan='\033[36m'
lightgrey='\033[37m'
darkgrey='\033[90m'
lightred='\033[91m'
lightgreen='\033[92m'
yellow='\033[93m'
lightblue='\033[94m'
pink='\033[95m'
lightcyan='\033[96m'
class bg:
black='\033[40m'
red='\033[41m'
green='\033[42m'
orange='\033[43m'
blue='\033[44m'
purple='\033[45m'
cyan='\033[46m'
lightgrey='\033[47m'

print(f"{colors.bold}{colors.fg.green}Success!")

Argument Parsing

import argparse

parser = argparse.ArgumentParser(description="description")
parser.add_argument("input", help="Input", nargs='?')
parser.add_argument("output", help="Output", nargs='?')
parser.add_argument("--optional", help="optional", action='append')

args = parser.parse_args()

if args.optional is not None:
    print("The optional input was provided.")

print(args.input)
print(args.output)

File Operations

  • x creates new file, returns error when it exists.
  • a appends to file, creates it when it does not exist.
  • w overwrites file, creates it when it does not exist.

Append "Append example" to file.txt:

f = open("file.txt", "a")
f.write("Append example")
f.close()

Skip First Couple of Lines

with open('file.txt') as f:
lines_after_2 = f.readlines()[2:]

Iteration

Range

for i in range(10):
print(i)

Deduplicate List

for i in mylist:
if i not in newlist:
newlist.append(i)

from collections import OrderedDict
newlist = list(OrderedDict.fromkeys(mylist))

Databases

TinyDB

Install: pip install tinydb

Example usage

from tinydb import TinyDB, Query

# Create DB
db = TinyDB('db.json')
db.insert({ 'type': 'OSFY', 'count': 700 })
db.insert({ 'type': 'EFY', 'count': 800 })
db.all()

# Update DB
db.update({'count': 1000}, Magazine.type == 'OSFY')
db.all()

# Search and List
Magazine = Query()
db.search(Magazine.type == 'OSFY')
db.search(Magazine.count > 750)

# Remove / Purge
db.remove(Magazine.count < 900)
db.all()
db.purge()
db.all()

# In-Memory Use
from tinydb.storages import MemoryStorage
db = TinyDB(storage=MemoryStorage)

SQLite

Example usage

import sqlite3

# Create DB
conn = sqlite3.connect('sqlite.db')
cursor = conn.cursor()
cursor.execute("CREATE TABLE IF NOT EXISTS exampletable (id integer PRIMARY KEY, login text, email text)")
conn.commit()

# Add entry
def sql_insert(data):
    login = data[0]
    cursor.execute(f'SELECT login FROM exampletable WHERE login = "{login}"')
    results = cursor.fetchall()
    if not results:
        cursor.execute('INSERT INTO exampletable (login, email) VALUES (?, ?)', data)
        conn.commit()
    else:
        print(f'User {login} already in database')

data = ('0xfab1', 'mail@example.com')
sql_insert(data)

# Read entry
def sql_fetch():
    cursor.execute('SELECT * FROM exampletable')
    rows = cursor.fetchall()
    return rows

print(sql_fetch())

Art

  • One liner code for half pyramid pattern: print('\n'.join('* ' * i for i in range(1, n + 1)))