python financial calculator

Foreword: Quantitative analysis of financial stocks must know more formula calculations, and hereby post a record of the formula knowledge learned.
1. Calculate the present value formula of future cash:

PV represents the performance value, FV represents the cash value obtained in the future, R refers to the discount rate, n refers to the cycle

def pv_f(fv,r,n):
    return fv/(1+r)**n
print(pv_f(100,0.1,1))

2. Formula for calculating the present value of perpetual annuities

PV refers to the present value of perpetual annuities, C refers to the equivalent cash paid at the end of each period, and R refers to the discount rate.

def pv_perpetuity(c,r):
    return c/r
print(pv_perpetuity(20,0.1))  #未来每年的年末收到20美元，年化折现率10%，那永续年金现值为200美元

3. The formula for calculating the present value of the growth perpetual annuity

g refers to a constant growth rate per period

def pv_growing_perpetuity(c,r,g):
    if(r<g):
        print('折现率r不能小于增长率g')
    else:
        return (c/(r-g))
print(pv_growing_perpetuity(20, 0.1, 0.08))

#4. Interest rate conversion

EAR effective annual rate (effective annual rate), APR given annual interest rate (annual percentage rate), m annual compound interest frequency

def EAR_rate(APR_rate, m):
    return ((1+APR_rate/m)**m-1)
print(EAR_rate(0.005,2))  #银行提供按半年复利年利率为5%的贷款转换成有效年利率
print(EAR_rate(0.051,4))  #银行提供按季复利年利率为5.1%的贷款转换成有效年利率