重复（df ）将给您一个逻辑向量（所有值由T / F组成），然后您可以将其用作数据帧行的索引。

duplicated(df) will give you a logical vector (all values consisting of either T/F), which you can then use as an index to your dataframe rows.

# indx will contain TRUE values wherever in df$var there is a duplicate
indx <- duplicated(df$var)
df[indx, ]  #note the comma 

你可以一起把它放在一起

You can put it all together in one line

df[duplicated(df$var), ]  # again, the comma, to indicate we are selected rows