النصوص (Strings)

word = "Python"
#       P  y  t  h  o  n
#       0  1  2  3  4  5
#      -6 -5 -4 -3 -2 -1

print(word[0])      # first character
print(word[-1])     # last character
print(word[0:3])    # slicing: from 0 up to (not including) 3
print(len(word))    # length

raw_email = "   Ahmed.Ali@Gmail.COM  "
raw_phone = "010-1234-5678"

email = raw_email.strip().lower()      # chain methods together
phone = raw_phone.replace("-", "")

print(email)
print(phone)

# Validate Egyptian mobile number
valid_prefixes = ("010", "011", "012", "015")
if len(phone) == 11 and phone.startswith(valid_prefixes):
    print("Valid number")
else:
    print("Invalid number")

product = "Laptop"
price = 23499.5
qty = 2

# f before the quotes, variables inside {}
print(f"{qty} x {product} = {price * qty:,.2f} EGP")
# :,.2f -> comma separators + 2 decimal places