用 Python 理財：打造小資族選股策略-股票買賣簡單計算
財經小知識
買賣股票需要多少錢?
摩擦成本 = 手續費 + 證交稅
習題1
"""
上課習題：
帳戶有100000元
1. 買一張股價為30的股票
2. 股價漲了20%
3. 賣出
請問帳戶現在有多少錢?
"""
account = 100000
stock_price = 30
buy_amount = 1
fee_ratio = 1.425 / 1000
tax_ratio = 3 / 1000
# 買股票，帳戶的錢變少
stock_value = stock_price * buy_amount * 1000
account = account - stock_value - stock_value * fee_ratio
# 股價漲
stock_price *= 1.2
# 賣股票，帳戶的錢變多
stock_value = stock_price * buy_amount * 1000
account = account + stock_value - stock_value * (fee_ratio + tax_ratio)
print(account)
# 105797.95
習題2
"""
設計一個函數，叫做calculate_earning
這個函數讀入買入價格、賣出價格、持有數量，並回傳獲利。
(不用考慮手續費)
"""
def calculate_earning(buy_price, sell_price, amount=1):
ret = (sell_price - buy_price) * amount * 1000
return ret
value = calculate_earning(30, 40, 2)
print(value)
# 20000