如何让 r 不删除 ggplot 中的一行 - geom_line

Question

I'm trying to produce a graph of growth rates over time based upon the following data which has blanks in two groups.

When I try to make a growth plot of this using geom_line to join points there is no line for group c.

I'm just wondering if there is anyway to fix this

Answer 1

One option would be to get rid of the missing values which prevent the points to be connected by the line:

Making use of the code from the answer I provided on your previous question but adding tidyr::drop_na :

Growthplot <- data.frame(
  Site = letters[1:4],
  July = 0,
  August = c(1, -1, NA, 2),
  September = c(3, 2, 3, NA)
)

library(ggplot2)
library(tidyr)
library(dplyr, warn=FALSE)

growth_df <- Growthplot %>%
  pivot_longer(-Site, names_to = "Month", values_to = "Length") %>%
  mutate(Month = factor(Month, levels = c("July", "August", "September"))) %>%
  drop_na()

ggplot(growth_df, aes(x = Month, y = Length, colour = Site, group = Site)) +
  geom_point() +
  geom_line()+
  labs(color = "Site", x = "Month", y = "Growth in cm")  +  
  theme(axis.line = element_line(colour = "black", size = 0.24))