rduplicatesuniquer-faq

How can I remove all duplicates so that NONE are left in a data frame?


There is a similar question for PHP, but I'm working with R and am unable to translate the solution to my problem.

I have this data frame with 10 rows and 50 columns, where some of the rows are absolutely identical. If I use unique on it, I get one row per - let's say - "type", but what I actually want is to get only those rows which only appear once. Does anyone know how I can achieve this?

I can have a look at clusters and heatmaps to sort it out manually, but I have bigger data frames than the one mentioned above (with up to 100 rows) where this gets a bit tricky.


Solution

  • This will extract the rows which appear only once (assuming your data frame is named df):

    df[!(duplicated(df) | duplicated(df, fromLast = TRUE)), ]
    

    How it works: The function duplicated tests whether a line appears at least for the second time starting at line one. If the argument fromLast = TRUE is used, the function starts at the last line.

    Boths boolean results are combined with | (logical 'or') into a new vector which indicates all lines appearing more than once. The result of this is negated using ! thereby creating a boolean vector indicating lines appearing only once.