Merge app_labels & label_categories using label_id as the common variable
app_label_cat <- merge(x = app_labels, y = label_categories, all = TRUE, by = 'label_id')
app_label_cat <- tbl_df(app_label_cat) # convert into `tibble`
app_label_cat
# A tibble: 460,366 x 3
label_id app_id category
<int> <chr> <chr>
1 1 <NA> <NA>
2 2 -2600987541603275322 game-game type
3 3 <NA> game-Game themes
4 4 -2600987541603275322 game-Art Style
5 5 -4507126529409281835 game-Leisure time
6 5 -781493088327916750 game-Leisure time
7 5 -8726376159123685147 game-Leisure time
8 5 -3009285907035616624 game-Leisure time
9 5 4214070236051361526 game-Leisure time
10 5 3489720147367481003 game-Leisure time
# ... with 460,356 more rows