R：ggplot2 x轴作为连续体打印，但需要作为离散值

Question

我的数据：

structure(list(YEAR = structure(1:10, .Label = c("1980", "1981", 
"1982", "1983", "1984", "1985", "1986", "1987", "1988", "1989"
), class = "factor"), lupas = c(1185, 822, 1340, 853, 3018, 1625, 
966, 1505, 1085, 1754)), .Names = c("YEAR", "lupas"), row.names = c(NA, 
-10L), class = c("tbl_df", "tbl", "data.frame"), drop = TRUE)

我使用dplyr中的group_by对数据进行分组。

str(df1)
Classes ‘tbl_df’, ‘tbl’ and 'data.frame':   10 obs. of  2 variables:
 $ YEAR : Factor w/ 10 levels "1980","1981",..: 1 2 3 4 5 6 7 8 9 10
 $ lupas: num  1185 822 1340 853 3018 ...
 - attr(*, "drop")= logi TRUE

我正在尝试绘制年份的图表，以及每年的“lupas”。就像时间序列图一样。

这是我的代码，但是会出错：

ggplot(df1,
   aes(x = YEAR, y = lupas)) +
geom_line()


geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?

这张图：

阅读此主题后：ggplot2 each group consists of only one observation

我已将代码更改为：

ggplot(df1,
   aes(x = YEAR, y = lupas)) +
geom_line(position=position_dodge(.1))

现在我收到这条消息：

ymax not defined: adjusting position using y instead
geom_path: Each group consist of only one observation. Do you need  to   adjust the group aesthetic?

Answer 1

也许这会有所帮助：

library(ggplot2)
p <- ggplot(df1, aes(x = YEAR, y = lupas, group = 1)) +  
    geom_point(color = "black") + geom_line(color = "blue")

修改

要在x轴上仅显示特定刻度，可以将scale_x_discrete()与breaks结合使用：

p <- ggplot(df1, aes(x = YEAR, y = lupas, group = 1)) +  
  geom_point(color = "black") + geom_line(color = "blue") +
  scale_x_discrete(breaks = c("1980", "1985", "1989"))