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pythonwolfram-mathematicawolfram-language
Gal Zajc
Gal Zajc

Reputation: 151

Python equivalent of Wolfram Table[]

In wolfram Mathematica, I use Table[] function all the time.

Example of Table function

enter image description here

i1^2 + i3^3 could be any function of parameters (i1,i3).

and

{i1, 1, 9, 2},
5,
{i3, 7, 3, -.5}

is the space of parameters.

For more details see the documentation: https://reference.wolfram.com/language/ref/Table.html

I can do this with a series of for loops in python like this:

import numpy as np



def f(i1,i3):
    return(i1**2+i3**3)
    
arr=np.array([[[
        
        f(i1,i3)
        
        for i3 in np.arange(7,2.5,-.5)]
        for i2 in np.arange(5)]
        for i1 in np.arange(1,11,2)]
        )
print(arr)

Is there a shorter, more compact way of doing it?

Upvotes: 4

Views: 1184

Answers (1)

userrandrand
userrandrand

Reputation: 171

I recently started python and this is is one of the things I miss from Mathematica. Below I give a function that answers the question but it only works when the output is a numerical table not a symbolic one. If the reader would like a symbolic table then FunctionMatrix in the python package sympy might help.

code:

import itertools
import numpy as np
    
def table(f,*arg) :
    return np.array([f(*a) for a in itertools.product(*arg)]).reshape(*map(len,arg))

Examples:

input: table(lambda a,b : a+b, np.arange(1,3),np.arange(1,5))

output: array([[2, 3, 4, 5],[3, 4, 5, 6]])

input: table(lambda a,b,c : a**2+b**3+c**4, np.arange(2,4),np.arange(1,5),np.arange(1,3))

output:

array([[[ 6, 21],
        [13, 28],
        [32, 47],
        [69, 84]],

        [[11, 26],
        [18, 33],
        [37, 52],
        [74, 89]]])

OP's example in the image is obtained with

table(lambda a,b,c : a**3+c**3,np.arange(1,11,2), np.arange(5), np.arange(7,2.5,-.5))

I was not able (did not really try that much) to translate what OP's code with for loops would be in mathematica and I did not know what arrays to use with the above table function

Upvotes: 0

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