Hari 4: Input, Konversi Tipe & Fungsi Bawaan

Menerima Input dari User

Fungsi input() menampilkan prompt dan menunggu user mengetik, lalu mengembalikan hasilnya sebagai string.

nama = input("Masukkan namamu: ")
print(f"Halo, {nama}!")

# PENTING: input() selalu mengembalikan string!
umur_str = input("Umur kamu: ")
print(type(umur_str))  # <class 'str'>

Konversi Tipe Data (Type Casting)

# String → Angka
umur   = int(input("Umur: "))
tinggi = float(input("Tinggi (cm): "))

# int() — potong desimal, tidak membulatkan
print(int(3.9))   # 3
print(int(-3.9))  # -3
print(int("42"))  # 42

# float()
print(float("3.14"))  # 3.14
print(float(7))       # 7.0

# str()
print(str(100))    # "100"
print(str(3.14))   # "3.14"
print(str(True))   # "True"

# bool()
print(bool(0))     # False
print(bool(""))    # False
print(bool(None))  # False
print(bool(1))     # True
print(bool("hai")) # True

Fungsi Bawaan (Built-in Functions) Penting

# Matematika
print(abs(-15))          # 15 — nilai absolut
print(round(3.14159, 2)) # 3.14
print(round(2.5))        # 2 (banker's rounding)
print(max(3, 7, 1, 9))   # 9
print(min(3, 7, 1, 9))   # 1
print(sum([1,2,3,4,5]))  # 15
print(pow(2, 10))         # 1024

# Info
print(len("Python"))     # 6
print(len([1,2,3]))       # 3
print(type(3.14))         # <class 'float'>
print(isinstance(3, int)) # True

# Urutan
angka = [3, 1, 4, 1, 5, 9]
print(sorted(angka))           # [1, 1, 3, 4, 5, 9]
print(sorted(angka, reverse=True))  # [9, 5, 4, 3, 1, 1]
print(list(range(1, 11)))      # [1, 2, ..., 10]

Modul math

import math

print(math.pi)          # 3.141592653589793
print(math.e)           # 2.718281828459045
print(math.sqrt(144))   # 12.0
print(math.ceil(3.2))   # 4  — bulatkan ke atas
print(math.floor(3.9))  # 3  — bulatkan ke bawah
print(math.factorial(5))# 120
print(math.log(100, 10))# 2.0 — log base 10