CODEWITHSUNDEEP
pythonarraysnumpyvectormultiplication
Amartin
Amartin

Reputation: 337

Multiplying two arrays in python with different lenghts

I want to know if it's possible to solve this problem. I have this values:

yf = (0.23561643, 0.312328767,  0.3506849315, 0.3890410958,  0.4273972602,  0.84931506)
z = (4.10592285e-05,  0.0012005020, 0.00345332906,  0.006367483, 0.0089151571,  0.01109750, 0.01718827)

I want to use this function (Discount factor) but it's not going to work because of the different lenghts between z and yf. 

def f(x): 
        res = 1/( 1 + x * yf)
        return res
f(z) 
output: ValueError: cannot evaluate a numeric op with unequal lengths

My question is that if it exists a way to solve this. The approximate output values are:

res = (0.99923, 0.99892, 0.99837, 0.99802, 0.99763, 0.99175)

Any help with this will be perfect and I want to thanks in advance to everyone who takes his/her time to read it or try to help.

Upvotes: 1

Views: 280

Answers (2)

mad_
mad_

Reputation: 8273

Find the minimum length and iterate. Can also covert to numpy arrays and that would avoid a step of iteration

import numpy as np
yf = (0.23561643, 0.312328767,  0.3506849315, 0.3890410958,  0.4273972602,  0.84931506)
z = (4.10592285e-05,  0.0012005020, 0.00345332906,  0.006367483, 0.0089151571,  0.01109750, 0.01718827)
x=min(len(yf),len(z))

res = 1/( 1 + np.array(z[:x]) * np.array(yf[:x]))

using numpy.multiply

res = 1/( 1 + np.multiply(np.array(z[:x]),np.array(yf[:x])))

Upvotes: 1

Rocky Li
Rocky Li

Reputation: 5958

Do you want array to broadcast to the whichever is the shorter? You can do this

def f(x): 
    leng = min(len(x), len(yf))
    x = x[:leng]
    new_yf = yf[:leng] # Don't want to modify global variable.
    res = 1/( 1 + x * new_yf)
    return res

and it should work.

Upvotes: 1

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