答疑问(二）

标签：ggplot2 R语言

在R上运行如下代码，结果如下：

Market_Size
# A tibble: 7 x 3
   year  size speed
  <dbl> <dbl> <dbl>
1  2009  44.4  NA  
2  2010  58.9  32.8
3  2011  89.4  51.6
4  2012 117.   31.1
5  2013 163.   39.3
6  2014 199.   21.8
7  2015 236.   18.8

ggplot() +    geom_bar(data = Market_Size, aes(x = year, y = size),  colour="gray", size=1)
Error: stat_count() must not be used with a y aesthetic.

于是我查找了一下函数的默认值：

?geom_bar
geom_bar(mapping = NULL, data = NULL, stat = "count",
  position = "stack", ..., width = NULL, binwidth = NULL,
  na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)

发现stat的默认值是“count”，于是我修改了默认值，再次作图：

ggplot() +    geom_bar(data = Market_Size, aes(x = year, y = size),  stat="identity", colour="gray", size=1)

大功告成！

geom_bar.jpeg