Problem & suggested fix in beginner tutorials - Loading Image Data

[jonathannathanaus]

Hi Team,

TLDR:
Please check the change in instruction from "/" to "\\" :

get_label <- function(file_path) {
        parts <- tf$strings$split(file_path, "/")
        parts[-2] %>% 
                tf$equal(classes) %>% 
                tf$cast(dtype = tf$float32)
}

Longer:
I was recently going through the loading image dataset tutorial, and got the following error when applying the below code:

Code:

# num_parallel_calls are going to be autotuned
labeled_ds <- list_ds %>%  dataset_map(preprocess_path, num_parallel_calls = tf$data$experimental$AUTOTUNE)

Error:

2022-04-09 12:16:47.207451: W tensorflow/core/framework/op_kernel.cc:1745] OP_REQUIRES failed at strided_slice_op.cc:108 : INVALID_ARGUMENT: slice index -1 of dimension 0 out of bounds.
Error in py_iter_next(it, completed) : 
  InvalidArgumentError: {{function_node __wrapped__IteratorGetNext_output_types_2_device_/job:localhost/replica:0/task:0/device:CPU:0}} slice index -1 of dimension 0 out of bounds.
	 [[{{node strided_slice}}]] [Op:IteratorGetNext]

After a bit of tinkering, I found that the get_label function was not splitting the directory path correctly. This resulted in the data_map function not being able to function correctly. This was because the file path containing the category was not being plit through tf$strings$split (split) and hence couldn't be compared through tf$equal(classes). Thus, the sep value of / was causing the error. Please see the TLDR section for the suggested fix.