如何在R ggplot2中的geom_smooth（facet_wrap）中传递多个公式？

Question

我想为每个因素拟合三个不同的函数（var.test）。我尝试了以下方法，但收到错误消息Warning messages: 1: Computation failed in stat_smooth() :invalid formula。还有其他方法可以同时读取多个公式吗？

set.seed(14)
df <- data.frame(
  var.test = c("T","T","T","T","M","M","M","M","A","A","A","A"),
  val.test = rnorm(12,4,5),
  x = c(1:12)
)

my.formula <- c(y~x + I(x^2), y~x, y~x + I(x^2))

ggplot(df, aes(x = x, y = val.test)) + geom_point() +
  geom_smooth(method="glm", formula = my.formula, 
              method.args = list(family = "poisson"), color = "black" ) + facet_grid(.~var.test)

Answer 1

每个 只能有一个公式geom_smooth()。您需要添加三个不同的geom_smooth层。您可以手动执行此操作

ggplot(df, aes(x = x, y = val.test)) + 
  geom_point() +
  geom_smooth(method="glm", formula = my.formula[[1]], method.args = list(family = "poisson"), color = "black" ) + 
  geom_smooth(method="glm", formula = my.formula[[2]], method.args = list(family = "poisson"), color = "black" ) + 
  geom_smooth(method="glm", formula = my.formula[[3]], method.args = list(family = "poisson"), color = "black" ) + 
  facet_grid(.~var.test)

或者你可以用来lapply帮助

ggplot(df, aes(x = x, y = val.test)) + 
  geom_point() +
  lapply(my.formula, function(x) geom_smooth(method="glm", formula = x, 
              method.args = list(family = "poisson"), color = "black" )) + 
  facet_grid(.~var.test)

如果您希望每个面板有不同的行，那么您可以过滤每个面板的数据。这里我们使用一个mapply助手并对每行的数据进行子集化。

ggplot(df, aes(x = x, y = val.test)) + 
  geom_point() +
  mapply(function(x, z) geom_smooth(method="glm", data=function(d) subset(d, var.test==z), formula = x, 
              method.args = list(family = "poisson"), color = "black" ),
         my.formula, c("A","M","T")) + 
facet_grid(.~var.test)