目录：

1. 还贷计算
2. 会计折旧
3. 字符串操作

还贷计算

完成这个函数对我这种学渣来说最困难的是公式，于是我直接上网找来了现成的

def pmt(rate, nper, pv):
    num = rate*(1+rate)**nper/((1+rate)**nper -1)
    payment = pv*num
    print (round(payment, 2))
# pmt(0.1, 10, 500000)

会计计算

def SLN(cost, salvage, nper):
    depreciation = (cost - salvage)/nper
    print (round(depreciation, 2))
# SLN(500000, 100000, 4)

def SYD(cost, life, period, salvage = 0):
    total = 0
    for i in range(life + 1):
        total += i
    numerator = life - (period -1)
    depreciation = (cost-salvage)*(numerator/total)
    print (round(depreciation, 2))
# SYD(500000, 3, 1)

def DB(rate, cost, life, period, salvage = 0):
    dep = cost - salvage
    if period > life:
        print ('折旧年限太小')
        sys.exit()
    elif period == life:
        for i in range(period - 1):
            dep -= dep*rate
        depreciation = dep
        print (round(depreciation, 2))
        sys.exit()
    for i in range(period):
        dep -= dep*rate
    depreciation = dep/9
    print (round(depreciation, 2))
# DB(0.1, 500000, 2, 2)

字符串操作

def LEFT(text, num_charc):
    container = []
    for i in range(num_charc):
        container.append(text[i])
    out = ''.join(container)
    print (out)
# LEFT('1233', 2)

申明
编程超级新手，肯定有很多不完善，包括代码可能显得有些冗杂。如果你有任何的建议，可以告诉我，谢谢你 ^_^

代码中没有太多的解释，如果你也是和我一样的新手，就多查查官方的documentation.