The Python Standard Libary is part of your Python installation. It contains a wide range of packages which may be helpful while building your Python masterpieces. This notebook lists some of the commonly used packages and their main functionalities.
import datetime as dt
local_now = dt.datetime.now()
print(f"local now: {local_now}")
utc_now = dt.datetime.utcnow()
print(f"utc now: {utc_now}")
# You can access any value separately:
print(
f"{local_now.year} {local_now.month} {local_now.day} {local_now.hour} {local_now.minute} {local_now.second}"
)
print(f"date: {local_now.date()}")
print(f"time: {local_now.time()}")
strftime()
¶For string formatting the datetime
formatted1 = local_now.strftime("%Y/%m/%d-%H:%M:%S")
print(formatted1)
formatted2 = local_now.strftime("date: %Y-%m-%d time:%H:%M:%S")
print(formatted2)
strptime()
¶For converting a datetime string into a datetime
object
my_dt = dt.datetime.strptime("2000-01-01 10:00:00", "%Y-%m-%d %H:%M:%S")
print(f"my_dt: {my_dt}")
tomorrow = local_now + dt.timedelta(days=1)
print(f"tomorrow this time: {tomorrow}")
delta = tomorrow - local_now
print(f"tomorrow - now = {delta}")
print(f"days: {delta.days}, seconds: {delta.seconds}")
print(f"total seconds: {delta.total_seconds()}")
import datetime as dt
from zoneinfo import ZoneInfo
naive_utc_now = dt.datetime.utcnow()
print(f"naive utc now: {naive_utc_now}, tzinfo: {naive_utc_now.tzinfo}")
# Localizing naive datetimes
UTC_TZ = ZoneInfo("UTC")
utc_now = naive_utc_now.replace(tzinfo=UTC_TZ)
print(f"utc now: {utc_now}, tzinfo: {utc_now.tzinfo}")
# Converting localized datetimes to different timezone
PARIS_TZ = ZoneInfo("Europe/Paris")
paris_now = utc_now.astimezone(PARIS_TZ)
print(f"Paris: {paris_now}, tzinfo: {paris_now.tzinfo}")
NEW_YORK_TZ = ZoneInfo("America/New_York")
ny_now = utc_now.astimezone(NEW_YORK_TZ)
print(f"New York: {ny_now}, tzinfo: {ny_now.tzinfo}")
import logging
# Handy way for getting a dedicated logger for every module separately
logger = logging.getLogger(__name__)
logger.setLevel(logging.WARNING)
logger.debug("This is debug")
logger.info("This is info")
logger.warning("This is warning")
logger.error("This is error")
logger.critical("This is critical")
There's a neat exception
function in logging
module which will automatically log the stack trace in addition to user defined log entry.
try:
path_calculation = 1 / 0
except ZeroDivisionError:
logging.exception("All went south in my calculation")
import logging
# This is only required for Jupyter notebook environment
from importlib import reload
reload(logging)
my_format = "%(asctime)s | %(name)-12s | %(levelname)-10s | %(message)s"
logging.basicConfig(format=my_format)
logger = logging.getLogger("MyLogger")
logger.warning("Something bad is going to happen")
logger.error("Uups, it already happened")
import logging
from pathlib import Path
# This is only required for Jupyter notebook environment
from importlib import reload
reload(logging)
logger = logging.getLogger("MyFileLogger")
# Let's define a file_handler for our logger
log_path = Path.cwd() / "my_log.txt"
file_handler = logging.FileHandler(log_path)
# And a nice format
formatter = logging.Formatter(
"%(asctime)s | %(name)-12s | %(levelname)-10s | %(message)s"
)
file_handler.setFormatter(formatter)
logger.addHandler(file_handler)
# If you want to see it also in the console, add another handler for it
# logger.addHandler(logging.StreamHandler())
logger.warning("Oops something is going to happen")
logger.error("John Doe visits our place")
import random
rand_int = random.randint(1, 100)
print(f"random integer between 1-100: {rand_int}")
rand = random.random()
print(f"random float between 0-1: {rand}")
If you need pseudo random numbers, you can set the seed
for random. This will reproduce the output (try running the cell multiple times):
import random
random.seed(5) # Setting the seed
# Let's print 10 random numbers
for _ in range(10):
print(random.random())
import re
secret_code = "qwret 8sfg12f5 fd09f_df"
# "r" at the beginning means raw format, use it with regular expression patterns
search_pattern = r"(g12)"
match = re.search(search_pattern, secret_code)
print(f"match: {match}")
print(f"match.group(): {match.group()}")
numbers_pattern = r"[0-9]"
numbers_match = re.findall(numbers_pattern, secret_code)
print(f"numbers: {numbers_match}")
import re
def validate_only_lower_case_letters(to_validate):
pattern = r"^[a-z]+$"
return bool(re.match(pattern, to_validate))
print(validate_only_lower_case_letters("thisshouldbeok"))
print(validate_only_lower_case_letters("thisshould notbeok"))
print(validate_only_lower_case_letters("Thisshouldnotbeok"))
print(validate_only_lower_case_letters("thisshouldnotbeok1"))
print(validate_only_lower_case_letters(""))