what can you do with an arduino code example

Example 1: can you do a join() in js without the commas

arr.join("")

Example 2: do i need do some set when i use GPU to train tensorflow model

from __future__ import absolute_import, division, print_function, unicode_literalsimport tensorflow as tfprint("Num GPUs Available: ", len(tf.config.experimental.list_physical_devices('GPU')))