Using geom_line with multiple groupings

Question

I have a table as follows:

> testsizes
    size value replicate lane
361   16  6898         1   L1
362   17 10707         1   L1
363   18  1786         1   L1         


        

Answer 1

As @joran pointed out, if ggplot could do this itself it would simply be concatenating the two groups anyway. So concatenating the two groups myself is the right way to go and gives me the desired result:

> testlengths$replane <- paste(testlengths$replicate, testlengths$lane, sep="_")

> testlengths
    size value replicate lane replane
361   16  6898         1   L1    1_L1
362   17 10707         1   L1    1_L1
363   18  1786         1   L1    1_L1
364   19  1721         1   L1    1_L1
365   20  2454         1   L1    1_L1
421   16  8486         2   L1    2_L1
422   17 26691         2   L1    2_L1
423   18  3241         2   L1    2_L1
424   19  5068         2   L1    2_L1
425   20  7579         2   L1    2_L1
481   16  4152         3   L1    3_L1
482   17  4452         3   L1    3_L1
483   18   899         3   L1    3_L1
484   19  1973         3   L1    3_L1
485   20  2595         3   L1    3_L1
571   16  8284         1   L2    1_L2
572   17  9045         1   L2    1_L2
573   18  5041         1   L2    1_L2
574   19  7160         1   L2    1_L2
575   20  9730         1   L2    1_L2
631   16  5639         2   L2    2_L2
632   17  9773         2   L2    2_L2
633   18  2433         2   L2    2_L2
634   19  3017         2   L2    2_L2
635   20  3864         2   L2    2_L2
691   16 10161         3   L2    3_L2
692   17 18609         3   L2    3_L2
693   18  3760         3   L2    3_L2
694   19  3543         3   L2    3_L2
695   20  4257         3   L2    3_L2

> ggplot(testlengths, aes(size, value, group=replane, colour=lane)) 
    + geom_line()

I guess the moral here is to do as much preprocessing of your table as you can before giving it to ggplot.