from functools import reduce
import numpy as np

def mor(x):
    """x: iterable of np.array."""
    return reduce(np.logical_or, x)

def mand(x):
    """x: iterable of np.array."""
    return reduce(np.logical_and, x)

def madd(x):
    """Performs element-wise string concatenation with multiple input arrays.

    Args:
        x: iterable of np.array.

    Returns: np.array.
    """
    for i, arr in enumerate(x):
        if type(arr.item(0)) is not str:
            x[i] = x[i].astype(str)
    return reduce(np.core.defchararray.add, x)