Python初学者。这个 Python 代码是否尽可能高效？

Question

这个问题/解决方案让我提出了另一个相关问题here - 非常感谢您的帮助！

根据最初的反馈更新了下面的当前代码

我是 Python 的新手（这是我的第二个程序）。我目前正在使用麻省理工学院的开放课件来介绍使用 Python Academic Earth videos 的 CS，并且我正在研究问题集 1 Viewable Here。我已经创建了这个程序，该程序在 12 个月内成功地重新创建了“测试用例 1”（不包括“结果”部分......仍在努力）但我的问题是，以下（我的）代码是否尽可能高效？我觉得我在可能没有必要的时候重复自己。 ：

原始代码：

balance = float(raw_input("Outstanding Balance: "))
interestRate = float(raw_input("Interest Rate: "))
minPayRate = float(raw_input("Minimum Monthly Payment Rate: "))
interestPaid = round((interestRate/12.0)*balance, 2)
minPayment = round(minPayRate*balance, 2)
principalPaid = round(minPayment-interestPaid, 2)
remainingBalance = round(balance-principalPaid, 2)
month = 1

while month < 12 :    
    if month > 1 :
        balance = remainingBalance
    interestPaid = round((interestRate/12.0)*balance, 2)
    minPayment = round(minPayRate*balance, 2)
    principalPaid = round(minPayment-interestPaid, 2)
    remainingBalance = round(balance-principalPaid , 2)   
    month = month+1

    print 'Month: ' + str(month)
    print 'Minimum monthly payment: ' + str(minPayment)
    print 'Principle paid: ' + str(principalPaid)
    print 'Remaining balance: ' + str(remainingBalance)

当前代码

balance = float(raw_input("Outstanding Balance: "))
interestRate = float(raw_input("Interest Rate: "))
minPayRate = float(raw_input("Minimum Monthly Payment Rate: "))

for month in xrange(1, 12+1):
    interestPaid = round(interestRate / 12.0 * balance, 2)
    minPayment = round(minPayRate * balance, 2)
    principalPaid = round(minPayment - interestPaid, 2)
    remainingBalance = round(balance - principalPaid, 2)

    print 'Month: %d' % (month,)
    print 'Minimum monthly payment: %.2f' % (minPayment,)
    print 'Principle paid: %.2f' % (principalPaid,)
    print 'Remaining balance: %.2f' % (remainingBalance,)

    balance = remainingBalance

如果您在此新代码中看到任何其他内容，请告诉我！

非常感谢帮助我走到今天这一步的人。

Answer 1

print "x: " + str(x)

应替换为：

print "x:", x

这是打印的特殊情况。

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将循环改为：

for month in xrange(1, 12+1):

删除第一个循环的检查，只需将 balance 设置为 remainingBalance 作为结束。

因为您手动增加月份，所以每次都打印错误的值。

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如果你的意思是效率和执行效率，你担心的是too soon。如果您的意思是复制代码，那么您确实在循环之前不必要地复制了数学。结合以上：

balance = float(raw_input("Outstanding Balance: "))
interestRate = float(raw_input("Interest Rate: "))
minPayRate = float(raw_input("Minimum Monthly Payment Rate: "))

for month in xrange(1, 12+1):    
  interestPaid = round(interestRate / 12.0 * balance, 2)
  minPayment = round(minPayRate * balance, 2)
  principalPaid = round(minPayment - interestPaid, 2)
  remainingBalance = round(balance - principalPaid, 2)   

  print 'Month:', month
  print 'Minimum monthly payment:', minPayment
  print 'Principle paid:', principalPaid
  print 'Remaining balance:', remainingBalance

  balance = remainingBalance

Answer 2

这与任何可能的效率问题无关*，但如果您正在做金融算术，您应该查看decimal 模块。否则，你会得到奇怪的rounding and representation errors。

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*更准确地说：它会降低效率，但会增加代码的正确性。

Answer 3

您应该使用string interpolation 或formatting 而不是传递给str() 并添加。

print 'Month: %d' % (month,)

Answer 4

对于一般的（速度）优化，您可能需要阅读An Optimization Anecdote