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NumPy Cookbook - Second Edition by Ivan Idris

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Creating a universal function

We can create a universal function from a Python function with the frompyfunc() NumPy function.

How to do it...

The following steps help us create a universal function:

  1. Define a simple Python function that doubles the input:
    def double(a):
        return 2 * a
  2. Create the universal function with frompyfunc(). Specify the number of input arguments and the number of objects (both are equal to 1) returned:
    from __future__ import print_function
    import numpy as np
    
    def double(a):
       return 2 * a
    
    ufunc = np.frompyfunc(double, 1, 1)
    print("Result", ufunc(np.arange(4)))

    The code prints the following output when executed:

    Result [0 2 4 6]
    

How it works...

We defined a Python function that doubles the numbers it receives. Actually, we can also have ...

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