Create a memory-mapped array comprised of the concatenation of every .npy file in a directory

concatenate_array_files.py

def concatenate_array_files(src_dir, file_name):
    """Create a memory-mapped array comprised of the concatenation of every
    .npy file in a directory

    Parameters
    ----------
    src_dir : str
        Directory of 2D .npy arrays with matching feature counts
    file_name : str
        File in which to save the concatenated arrays
    """
    total_samples = 0
    for f in os.listdir(src_dir):
        # Load the next array
        pat_arr = np.load(os.path.join(src_dir, f), mmap_mode='r')
        n_samples, n_features = pat_arr.shape
        total_samples += n_samples

        #print("**************")
        #print("File         : " + f)
        #print("n_samples    : " + str(n_samples))
        #print("total_samples: " + str(total_samples))

        # Load the concatenated file
        big_arr = np.memmap(target_file, dtype = np.float32, mode='w+', shape=(total_samples, n_features))
        big_arr[:n_samples, :] = pat_arr