如何为R中的大范围的小平面网格拟合轴标签

Question

我有这个名为d的数据。我使用下面的代码绘制数据，但X轴的范围非常高。如何使X轴标签与图形一致？我也想按顺序绘制它们，从chr1到chr16。谢谢你的帮助。

    d<- structure(list(chr = c("chr10", "chr10", "chr10", "chr11", "chr11", 
"chr11", "chr12", "chr12", "chr12", "chr13", "chr13", "chr13", 
"chr14", "chr14", "chr14", "chr15", "chr15", "chr15", "chr16", 
"chr16", "chr16", "chr1", "chr1", "chr1", "chr2", "chr2", "chr2", 
"chr3", "chr3", "chr3", "chr4", "chr4", "chr4", "chr5", "chr5", 
"chr5", "chr6", "chr6", "chr6", "chr7", "chr7", "chr7", "chr8", 
"chr8", "chr8", "chr9", "chr9", "chr9"), start = c(6, 14, 19, 
3, 10, 16, 60, 73, 80, 4, 11, 27, 67, 75, 81, 2, 7, 15, 13, 99, 
142, 1, 8, 21, 49, 53, 78, 92, 121, 165, 35, 42, 47, 5, 9, 17, 
12, 20, 34, 44, 51, 56, 61, 66, 94, 18, 31, 37), stop = c(6, 
14, 19, 3, 10, 16, 60, 73, 80, 4, 11, 27, 67, 75, 81, 2, 7, 15, 
13, 99, 142, 1, 8, 21, 49, 53, 78, 92, 121, 165, 35, 42, 47, 
5, 9, 17, 12, 20, 34, 44, 51, 56, 61, 66, 94, 18, 31, 37), density = c(10, 
4, 1, 13, 1, 1, 18, 48, 526, 3, 1, 1, 13, 74, 177, 1, 3, 5, 9432, 
3, 5, 1, 32, 1, 60, 4, 3, 2, 1, 10, 4, 10, 6, 6, 2, 3, 5, 65220, 
11136, 1, 25, 36, 5, 6, 1, 4, 7, 11)), .Names = c("chr", "start", 
"stop", "density"), row.names = c(NA, -48L), class = "data.frame")

我的代码：

library(ggplot2)
  ggplot(d, aes(start, density)) +
  geom_line(alpha = 0.9) +
  facet_grid(. ~ chr) +
  labs(title = "Density profiles along the chromosomes",
       x = "Coordinate, bp",
       y = "Density") +
  theme_bw()

Answer 1

我认为不可能为每个方面单独设置轴刻度。你可能最好不要在网格中安排小平面。

d$chr <- factor(d$chr, levels = c('chr1', 'chr2', 'chr3', 'chr4', 'chr5', 'chr6', 'chr7', 'chr8',
                                  'chr9', 'chr10', 'chr11', 'chr12', 'chr13', 'chr14', 'chr15', 'chr16'))

library(ggplot2)
ggplot(d, aes(start, density)) +
  geom_line(alpha = 0.9) +
  facet_wrap(~ chr, nrow = 4, scales = "free_x") +
  labs(title = "Density profiles along the chromosomes",
       x = "Coordinate, bp",
       y = "Density") +
  theme_bw()