Snippets

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:

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

• lambda function example using square root:

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

Create a random string ``` py title="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

  py title="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

``` py title="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

``` py title="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

``` py title="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

``` py
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', '[email protected]')
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)))