如何壓縮我的代碼？ （格式和計算

Question

抱歉，我是編碼新手，所以如果這是一個業余問題，我深表歉意。 一個練習要求我創建代碼來計算 1,2 和 3 年投資的 4% 利息。 我已經復制了很多代碼，並且想知道如何以不同的方式進行操作：以更簡潔的方式。

例如，是否有可能將每年都轉換成這樣的float(year1, year2, year3)以適應多行代碼？

startingBalance = input("Please enter your starting bank balance: ")
startingBalance = int(startingBalance)

year1 = (startingBalance * 1.04)
year2 = (year1 * 1.04)
year3 = (year2 * 1.04)
year1 = "{0:.2f}".format(year1)
year2 = "{0:.2f}".format(year2)
year3 = "{0:.2f}".format(year3)


print("Starting Balance: " + str(startingBalance) + "\n" + "Year 1 Balance: " + year1 + "\n" + "Year 2 Balance: " + year2 + "\n" + "Year 3 Balance: " + year3)

answer=str(input("would you like to withdraw your profits? Y/N: "))
if answer in ['Y', 'y']:
  startingBalance = float(startingBalance)
  year1 = float(year1)
  year2 = float(year2)
  year3 = float(year3)
  year1Profit = year1 - startingBalance
  year1Profit = "{0:.2f}".format(year1Profit)
  year2Profit = year2 - startingBalance
  year2Profit = "{0:.2f}".format(year2Profit)
  year3Profit = year3 - startingBalance
  year3Profit = "{0:.2f}".format(year3Profit)
  str(year3Profit)
  print("Year   | Balance | Profit " + "\n" + "Year 1  " + str(year1) + "       " + year1Profit  + "\n" + "Year 2  " + str(year2) + "       " + year2Profit  + "\n" + "Year 3  " + str(year3) + "       " + year3Profit)
elif answer in ['N', 'n']:
  print("Goodbye")
else:
  print("Invalid Entry")

Answer 1

從技術上講，這是一行：

year1, year2, year3 = float(year1), float(year2), float(year3)

但是我認為如果您在初始化后不更改變量的類型會更清楚。 您可以始終將它們保留為浮點數，將打印行更改為：

print("Starting Balance: " + str(startingBalance) + "\n" + "Year 1 Balance: " + "{0:.2f}".format(year1) + "\n" + "Year 2 Balance: " + "{0:.2f}".format(year2) + "\n" + "Year 3 Balance: " + "{0:.2f}".format(year3))

這使您免於轉換為字符串並再次轉換回來。

Answer 2

這個問題在Code Review中可能更合適，但是：

year1 = "{0:.2f}".format(year1)

可以替換為：

year1 = round(year1, 2)

在我推薦使用一種類型的相同代碼中使用 .format 和 print("foo" + bar)：

如果是 Python3.6 或更高版本，則為 F 字符串

print(f"Starting Balance: {startingBalance}\nYear 1 Balance: {year1}\nYear 2 Balance: {year2}\nYear 3 Balance: {year3}")

.format 如果 Python2 或 3 < 3.6

print("Starting Balance: {}\nYear 1 Balance: {}\nYear 2 Balance: {}\nYear 3 Balance: {}".format(startingBalance, year1, year2, year3))

無需將 str() 放在這里：

answer=str(input("would you like to withdraw your profits? Y/N: "))

input() 總是返回一個字符串。

當你想要（我猜）列表而不是一堆空格（丑陋）時使用“\ t”：

print("Year   | Balance | Profit " + "\n" + "Year 1  " + str(year1) + "       " + year1Profit  + "\n" + "Year 2  " + str(year2) + "       " + year2Profit  + "\n" + "Year 3  " + str(year3) + "       " + year3Profit)

同樣的事情在這里使用 f-strings 或 .format 來格式化你的字符串。

Answer 3

為避免編寫相同的代碼，您可以創建 function 來計算最終余額和利潤。 然后您可以使用其他答案來了解如何格式化變量並返回它們

def compute_year(starting_balance, number_of_year):
    return (startingBalance * 1.04 ** number_of_year, startingBalance * 1.04 ** number_of_year - startingBalance)

year1, year1Profit = compute_year(startingBalance, 1) 
year2, year2Profit = compute_year(startingBalance, 2) 
year3, year3Profit = compute_year(startingBalance, 3)

Answer 4

是的，很有可能，當你發現自己在寫重復的代碼行時，嘗試使用函數！ 這樣，您只需定義一次表達式！

例子：

year1 = (startingBalance * 1.04)
year2 = (year1 * 1.04)
year3 = (year2 * 1.04)

可以改成

def interest(balance):
    return balance * 1.04

year1 = interest(startingBalance)
year2 = interest(year1)

但這似乎仍然是重復的，對吧？ 現在嘗試使用for循環：

current_balance = startingBalance
for year in range(4):
    current_balance = interest(current_balance)
    print(current_balance)

現在在每個循環中，您可以打印新余額的值，最后在 printg 行中添加一個漂亮的 output：您可以得到如下內容：

def interest(balance, years):
    return balance * (1.04 ** years)


def print_gains(balance, year):
    header = 'Year | Balance    | Profit   '
    print(header)
    print('-' * len(header))
    for year in range(1 + year):
        new_balance = interest(balance, year)
        print('%5d| %10.2f | %10.2f' % (year, new_balance, new_balance - balance))
    print()


def main():
    print_gains(10000, 5)

main()

產生以下 output：

Year | Balance    | Profit
-----------------------------
    0|   10000.00 |       0.00
    1|   10400.00 |     400.00
    2|   10816.00 |     816.00
    3|   11248.64 |    1248.64
    4|   11698.59 |    1698.59
    5|   12166.53 |    2166.53

我希望這可以幫助你！