Using geom_line with multiple groupings
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
364 19 1721 1 L1
365 20 2454 1 L1
421 16 8486 2 L1
422 17 26691 2 L1
423 18 3241 2 L1
424 19 5068 2 L1
425 20 7579 2 L1
481 16 4152 3 L1
482 17 4452 3 L1
483 18 899 3 L1
484 19 1973 3 L1
485 20 2595 3 L1
571 16 8284 1 L2
572 17 9045 1 L2
573 18 5041 1 L2
574 19 7160 1 L2
575 20 9730 1 L2
631 16 5639 2 L2
632 17 9773 2 L2
633 18 2433 2 L2
634 19 3017 2 L2
635 20 3864 2 L2
691 16 10161 3 L2
692 17 18609 3 L2
693 18 3760 3 L2
694 19 3543 3 L2
695 20 4257 3 L2
> dput(testsizes)
structure(list(size = c(16L, 17L, 18L, 19L, 20L, 16L, 17L, 18L,
19L, 20L, 16L, 17L, 18L, 19L, 20L, 16L, 17L, 18L, 19L, 20L, 16L,
17L, 18L, 19L, 20L, 16L, 17L, 18L, 19L, 20L), value = c(6898L,
10707L, 1786L, 1721L, 2454L, 8486L, 26691L, 3241L, 5068L, 7579L,
4152L, 4452L, 899L, 1973L, 2595L, 8284L, 9045L, 5041L, 7160L,
9730L, 5639L, 9773L, 2433L, 3017L, 3864L, 10161L, 18609L, 3760L,
3543L, 4257L), replicate = c("1", "1", "1", "1", "1", "2", "2",
"2", "2", "2", "3", "3", "3", "3", "3", "1", "1", "1", "1", "1",
"2", "2", "2", "2", "2", "3", "3", "3", "3", "3"), lane = c("L1",
"L1", "L1", "L1", "L1", "L1", "L1", "L1", "L1", "L1", "L1", "L1",
"L1", "L1", "L1", "L2", "L2", "L2", "L2", "L2", "L2", "L2", "L2",
"L2", "L2", "L2", "L2", "L2", "L2", "L2")), .Names = c("size",
"value", "replicate", "lane"), row.names = c(361L, 362L, 363L,
364L, 365L, 421L, 422L, 423L, 424L, 425L, 481L, 482L, 483L, 484L,
485L, 571L, 572L, 573L, 574L, 575L, 631L, 632L, 633L, 634L, 635L,
691L, 692L, 693L, 694L, 695L), class = "data.frame")
I want to make a line plot using ggplot that shows the change in value across sizes. At the moment I have this, amongst the other combinations I have tried:
ggplot(testlengths, aes(size, value, group=replicate, colour=replicate))
+ geom_line()
It looks like its trying to incorporate both lanes into the same series. But I can't find a way to set the lanes as another factor to group on. I want the lines to be grouped based on both the replicate and lane categories. The lanes should be coloured but the replicates do not need to be distinguished between each other.
I am aware that I can probably achieve this by concatenating the two groups into one group beforehand. However, before I go down that route, I am wandering if ggplot can group by more than one grouping in a line plot without facets (I need to use facets later for another grouping)? I feel like it should be able to.
Answer
Based off my comment about interacting the two:
ggplot(testsizes, aes(x = size, y = value,
group = interaction(replicate, lane),
colour = lane)) +
geom_line()
Which gives:
