Python Tutorial (14): datetime, math, dan random

import datetime
 
# Tanggal dan waktu saat ini
now = datetime.datetime.now()
today = datetime.date.today()
 
print(now)           # 2026-05-05 14:30:00.123456
print(today)         # 2026-05-05
print(now.year, now.month, now.day)
print(now.hour, now.minute, now.second)

import datetime
 
d = datetime.date(2026, 5, 5)
t = datetime.time(14, 30, 0)
dt = datetime.datetime(2026, 5, 5, 14, 30, 0)
 
# Dari string
parsed = datetime.datetime.strptime("2026-05-05 14:30", "%Y-%m-%d %H:%M")
formatted = parsed.strftime("%d/%m/%Y %H:%M")   # '05/05/2026 14:30'

import datetime
 
today = datetime.date.today()
tomorrow = today + datetime.timedelta(days=1)
week_ago = today - datetime.timedelta(weeks=1)
in_3_hours = datetime.datetime.now() + datetime.timedelta(hours=3)
 
# Selisih dua tanggal
deadline = datetime.date(2026, 12, 31)
days_left = (deadline - today).days
print(f"Sisa {days_left} hari")

from datetime import datetime, timezone, timedelta
 
# UTC
utc_now = datetime.now(timezone.utc)
 
# Timezone custom (WIB = UTC+7)
WIB = timezone(timedelta(hours=7))
wib_now = datetime.now(WIB)
 
# Konversi
utc_now.astimezone(WIB)

import math
 
math.pi          # 3.141592653589793
math.e           # 2.718281828459045
 
math.sqrt(16)    # 4.0
math.pow(2, 10)  # 1024.0
math.log(100, 10)  # 2.0 (log base 10)
math.log2(8)     # 3.0
math.log10(1000) # 3.0
 
math.ceil(4.2)   # 5
math.floor(4.8)  # 4
math.trunc(4.8)  # 4
 
math.sin(math.pi / 2)   # 1.0
math.cos(0)             # 1.0
math.degrees(math.pi)   # 180.0
math.radians(180)       # 3.14159...
 
math.factorial(5)  # 120
math.gcd(48, 18)   # 6 (greatest common divisor)
math.isnan(float("nan"))  # True
math.isinf(float("inf"))  # True

# Untuk operasi dasar, operator cukup
2 ** 10          # 1024
abs(-5)          # 5 (built-in)
 
# math untuk fungsi transcendental dan utilitas
import math
math.sqrt(2)     # tidak ada operator sqrt

import random
 
random.random()              # float 0.0 <= x < 1.0
random.randint(1, 10)        # integer inclusive 1-10
random.uniform(1.0, 10.0)    # float dalam range
 
items = ["apel", "jeruk", "mangga"]
random.choice(items)         # satu elemen acak
random.choices(items, k=3)   # dengan replacement
random.sample(items, 2)      # tanpa replacement
 
random.shuffle(items)        # in-place shuffle
 
# Seed untuk reproducibility (testing)
random.seed(42)
random.randint(1, 100)   # selalu sama jika seed sama

import random
import secrets
 
# random: simulasi, game, sampling (BUKAN untuk keamanan)
random.randint(1000, 9999)
 
# secrets: token, password, kriptografi
secrets.token_hex(16)        # 'a3f2b1...'
secrets.choice("abcdef")     # aman untuk security

import statistics
 
data = [4, 7, 13, 16, 23, 24, 25, 29, 30, 31]
 
statistics.mean(data)        # 20.2
statistics.median(data)      # 24.5
statistics.mode([1, 2, 2, 3])  # 2
statistics.stdev(data)       # sample standard deviation
statistics.variance(data)

from datetime import date
 
def calculate_age(birth_date: date) -> int:
    today = date.today()
    age = today.year - birth_date.year
    if (today.month, today.day) < (birth_date.month, birth_date.day):
        age -= 1
    return age
 
birth = date(1995, 8, 15)
print(f"Umur: {calculate_age(birth)} tahun")

from datetime import datetime, timedelta
 
def is_expired(created_at: datetime, ttl_days: int) -> bool:
    expiry = created_at + timedelta(days=ttl_days)
    return datetime.now() > expiry
 
token_created = datetime(2026, 4, 1)
print(is_expired(token_created, ttl_days=30))