plotly heatmap doesn't take a dataframe

The figure reference documentation says

plot_ly(df, type="heatmap"[, ...])

the df in the code above indicates a data frame
The code below doesn't work

url <- "http://datasets.flowingdata.com/ppg2008.csv"
nba_players <- read.csv(url, row.names = 1)

plot_ly(nba_players, type = "heatmap")

A solution is to use a data.matrix

plot_ly(z = data.matrix(nba_players), 
           x = colnames(nba_players), 
           y = row.names(nba_players), 
           type = "heatmap")

先使用提供的 CSV 重現文件中的 plot_ly(nba_players, type = "heatmap") 範例，然後檢查熱圖 figure-reference 路徑。完成的標準是：要嘛如文件所述接受資料框，要嘛該參考內容清楚說明所需的矩陣轉換及其 x/y 標籤。