Web scraping with Spotify API-CodePudding

I tried to get 50 songs for each genre and put them together in a data frame with the genre name, but I got following error.

Error : object 'res' not found

I know that the undefined object is causing the problem, but I don't know how to do with it. Could you shed some light on this?

**Language:R, Environment: Exploratory Public**

    genres <- RETRY('GET', url = 'https://api.spotify.com/v1/recommendations/available-genre-seeds', query = list(access_token = get_spotify_access_token(), limit=150), quiet = TRUE) %>% content()

  m <- do.call(rbind,lapply(genres$genre, function(x) if(is.null(x)) NA else c(x)))
  genres_df <- as.data.frame(m)

  colnames(genres_df) <- c("genre")

　get_genre_track <- function(genre){ 
    track_check <- RETRY('GET', url = paste0("https://api.spotify.com/v1/search?query=genre:",genre),  query = list(type="track",limit = 50, offset = 0, access_token = get_spotify_access_token()), quiet = TRUE) %>% content()

    track_count <- 50

    df <- map_df(1:length(res$tracks$items), function(this_row) {
        tryCatch({
        this_track <- res$tracks$items[[this_row]]
        name <- this_track$name
        genre <- genre
        list(name = name, genre = genre)
      }, error = function(e){
          NULL
      })
    })
  }
  tracks_df <- lapply(genres_df$genre, get_genre_track) %>% bind_rows()
  tracks_df
}

(Required library installation and user information are omitted)

CodePudding user response：

In the script you've linked above, res is defined as follows:

res <- RETRY('GET', url = paste0("https://api.spotify.com/v1/search?query=genre:",genre), query = list(type="track",limit = 50, offset = numoffset, access_token = get_spotify_access_token()), quiet = TRUE) %>% content()

Whereas in your code, you seem to have renamed that variable to track_check:

track_check <- RETRY('GET', url = paste0("https://api.spotify.com/v1/search?query=genre:",genre),  query = list(type="track",limit = 50, offset = 0, access_token = get_spotify_access_token()), quiet = TRUE) %>% content()

So don't refer to it as res$tracks$items, but track_check$tracks$items.