Hi experts,
I am using python 3. I got a module interest.py (see attachment).
But when I tried to use this module with input in the command line, it
gives error
In [1]: import interest
In [2]: interest.py A=10 p=5 n=730
File "<ipython-input-2-82892ebb874e>", line 1
interest.py A=10 p=5 n=730
^
SyntaxError: invalid syntax
May you please tell me how to solve it?
This file "interest.py" is in the path of desktop. I think it is not a
default path for Spyder. So I added its path via "Tools" --> "PYTHONPATH
manager". Is it correct?
By the way, I am using IPython in Spyder (version, 2.3.2), my computer is
running Windows 7.
Thanks a lot.
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"""
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
_filename = sys.argv[0]
_usage = """
Usage: %s A=10 p=5 n=730
Program computes and prints the 4th parameter'
(A, A0, p, or n)""" % _filename
from math import log as ln
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-14):
"""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(p_computed, p) and \
float_eq(n_computed, n)
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 = ''
for statement in sys.argv[1:]:
init_code += statement + '\n'
# more elegant code:
# init_code = '; '.join(sys.argv[1:])
compute_missing_parameter(init_code)
