import math


def vdist(vect1,vect2):
    """
    This function returns the euclidean distance (the straight-line distance)
    between two vector coordinates.
    The distance between two points is the length of the vector joining them.

    Parameters
    ----------

    vect1:
        *float list*. The first vector - in the format[x,y,z]
        (or [x,y,z,0] for affine transformations in an homogeneous space).

    vect2:
        *float list*. The second vector - in the format [x,y,z]
        (or [x,y,z,0] for affine transformations in an homogeneous space).
    """
    joiningVect = [vect1[0] - vect2[0], vect1[1] - vect2[1], vect1[2] - vect2[2]]
    return math.sqrt(joiningVect[0] * joiningVect[0] + joiningVect[1] * joiningVect[1] + joiningVect[2] * joiningVect[2])