我不知道在这里问随机编码问题是否被认为是“可以”，但是在这里。感谢有兴趣为我解决这个问题的人。
请注意，这应该是一个模块，但是尝试从带有参数的终端运行它时出现了我的错误。
测试运行在底部，显示错误。
https://github.com/Kwantonium/Homework/blob/master/interest.py
"""
Module for computing with interest rates.
Symbols: A is present amount, A0 is initial amount,
n counts days, and p is the interest rate per year.
Given three of these parameters, the fourth can be
computed as follows:
A = present_amount(A0, p, n)
A0 = initial_amount(A, p, n)
n = days(A0, A, p)
p = annual_rate(A0, A, n)
"""
import sys
from math import log as ln
_filename = sys.argv[0]
_usage = """
Usage: %s A=10 p = 5 n = 730
Program computes and prints the 4th parameter. Enter parameter "test" to test functionality.
(A, A0, p, or n)""" % _filename
def present_amount(A0, p, n):
return A0*(1+p/(360.0*100))**n
def initial_amount(A, p, n):
return A*(1+p/(360.0*100))**(-n)
def days(A0, A, p):
return ln(A/A0)/ln(1+p/(360.0*100))
def annual_rate(A0, A, n):
return 360*100*((A/A0)**(1.0/n)-1)
def test_all_functions():
# Compatible values
A = 2.2133983053266699; A0 = 2.0; p = 5; n = 730
# Given three of these, compute the remaining one
# and compare with the correct value (in parenthesis)
A_computed = present_amount(A0, p, n)
A0_computed = initial_amount(A, p, n)
n_computed = days(A0, A, p)
p_computed = annual_rate(A0, A, n)
def float_eq(a, b, tolerance=1E-12):
# Return True if a == b within the tolerance
return abs(a-b) < tolerance
success = float_eq(A_computed, A) and\
float_eq(A0_computed, A0) and\
float_eq(n_computed, n) and\
float_eq(p_computed, p)
msg = """ Computations failed (correct answers in parenthesis):
A=%g (%g)
A0=%g (%.1f)
n=%d (%d)
p=%g (%.1f)""" % (A_computed, A, A0_computed, A0, n_computed, n, p_computed, p)
assert success, msg
def compute_missing_parameter(init_code):
try:
exec(init_code)
except SyntaxError as e:
print(e)
print(init_code)
sys.exit(1)
# Find missing parameter
try:
if "A=" not in init_code:
print("A =", present_amount(A0, p, n))
elif "A0=" not in init_code:
print("A0 =", initial_amount(A, p, n))
elif "n=" not in init_code:
print("n =", days(A0, A, p))
elif "p=" not in init_code:
print("p =", annual_rate(A0, A, n))
except NameError as e:
print(e)
sys.exit(1)
except ValueError:
print("Illegal values in input:", init_code)
sys.exit(1)
if __name__ == "__main__":
if len(sys.argv) == 1:
print(_usage)
elif len(sys.argv) == 2 and sys.argv[1] == "test":
test_all_functions()
else:
init_code = ";".join(sys.argv[1:])
compute_missing_parameter(init_code)
"""
Test run(interest.py):
In [125]: run interest A=2 A0=1095 p=100
Traceback (most recent call last):
File "C:\Users\quant\OneDrive\Skole\Programmering\pyprog\myfiles\interest.py", line 107, in <module>
compute_missing_parameter(init_code)
File "C:\Users\quant\OneDrive\Skole\Programmering\pyprog\myfiles\interest.py", line 94, in compute_missing_parameter
sys.exit(1)
name 'A0' is not defined
An exception has occurred, use %tb to see the full traceback.
SystemExit: 1
"""