return a function with partial argument embedded-CodePudding

I have a function which takes two numpy arrays, x and y, as arguments. I want to be able to pass in only one argument, y. How can I return a function that accepts x, with y embedded in original function?

For example:

def z(x: [x1, x2, x3], y: [y1, y2, y3]):
    return x1 * y1   x2 * y2   x3 * y3

I want z(y=[2, 3, 4]) to return x1 * 2 x2 * 3 x3 * 4 as a new function.

CodePudding user response：

Use functools.partial:

>>>  from functools import partial
>>> z_with_y = partial(z, y=[2,3,4])
>>> z_with_y([5,6,7])
56
>>> z([5,6,7], [2,3,4])
56

CodePudding user response：

Given z = np.dot, as in your example, or any other 2-arg function, you can make a partial fucuntion

def z1(y):
    return lambda x: z(x, y)

Without using lambda:

def z1(y):
    def inner(x):
        return z(x, y)
    return inner