嵌入式函数返回None [英] Embedded function returns None

问题描述

我的函数返回 None 。我已经检查过，以确保所有的操作都正确，并且我为每个函数都有一个return语句。

  def parameter_function（principal，annual_interest_rate，duration）：
n = float（duration * 12）
如果annual_interest_rate == 0：
r = float（principal / n）
其他：
r = float（annual_interest_rate / 1200）
p = principal 
 return（p，r，n）
 
 def monthly_payment_function（p，r，n）：
 monthly_payment = p *（（r *（（1 + r）** n））/（（（1 + r）** n） -  1））
 
结果= monthly_payment_function p，r，n）
返回结果
  

解决方案

monthly_payment_function 不会返回任何内容。将 monthly_payment = 替换为 return （即'return'后跟一个空格）。

你还有一个无条件的 return ，在 def monthly_payment_function 之前，这意味着它永远不会被调用说话，它甚至从来没有被定义）。

你也是随机混合单位，你的变量名可以使用一些帮助：

  from __future__ import division＃Python 2.x：int / int给出float b 
 $ b MONTHS_PER_YEAR = 12 
 
 def month_payment（本金，pct_per_year，年）：
月=年* MONTHS_PER_YEAR 
如果pct_per_year == 0：
返回本金/月
其他：
 rate_per_year = pct_per_year / 100. 
 rate_per_month = rate_per_year / MONTHS_PER_YEAR 
 rate_compounded =（1. + rate_per_month）** months  -  1. 
 return principal * rate_per_month *（1. + rate_compounded）/ rate_compounde d 
  

My function returns None. I have checked to make sure all the operations are correct, and that I have a return statement for each function.

def parameter_function(principal, annual_interest_rate, duration):
    n = float(duration * 12)
    if annual_interest_rate == 0:
        r = float(principal / n)
    else:
        r = float(annual_interest_rate / 1200)
    p = principal
    return (p, r, n)

    def monthly_payment_function(p, r, n):
        monthly_payment = p * ((r * ((1 + r) ** n)) / (((1 + r) ** n) - 1))

    result = monthly_payment_function(p, r, n)
    return result

解决方案

monthly_payment_function does not return anything. Replace monthly_payment= with return (that's 'return' followed by a space).

Also you have an unconditional return before def monthly_payment_function, meaning it never gets called (strictly speaking, it never even gets defined).

Also you are pretty randomly mixing units, and your variable names could use some help:

from __future__ import division    # Python 2.x: int/int gives float

MONTHS_PER_YEAR = 12

def monthly_payment(principal, pct_per_year, years):
    months = years * MONTHS_PER_YEAR
    if pct_per_year == 0:
        return principal / months
    else:
        rate_per_year   = pct_per_year / 100.
        rate_per_month  = rate_per_year / MONTHS_PER_YEAR
        rate_compounded = (1. + rate_per_month) ** months - 1.
        return principal * rate_per_month * (1. + rate_compounded) / rate_compounded

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