英文:
Altering the colour of a specific point in a ggplot
问题
我想更改数据框中特定点的颜色，注意我并没有绘制条件。
library(ggplot2)colpf <- c(0, 0, 0, 1, 1, 1, 2, 2, 2)coldf <- c(0, 1, 2, 0, 1, 2, 0, 1, 2)x <- seq(0, 8, 1)y <- seq(0, 8, 1)df <- data.frame(colpf, coldf, x, y)ggplot(data = df) +geom_point(aes(x = x, y = y))
我想将colpf等于1且coldf等于1的点（例如，红色）设为特殊颜色。在这种情况下，我相信这将有一个简单的解决方案，然而我的思维似乎无法理解它。谢谢。
英文:
I would like to change the colour of a specific point in a dataframe, note that I am not plotting the condition.
library(ggplot2)colpf <- c(0,0,0,1,1,1,2,2,2)coldf <- c(0,1,2,0,1,2,0,1,2)x <- seq(0,8,1)y <- seq(0,8,1)df <- data.frame(colpf,coldf,x,y)ggplot(data = df) +geom_point(aes(x=x,y = y))
I would like to make the point which corresponds to colpf = 1 and coldf=1, say, red. In this case I believe it would be the point (4,4). I believe this will have a simple solution however my mind cannot seem to grasp it. Thank you.
答案1
得分: 3
创建一个指示变量，用于指示条件是否满足。将颜色美学映射到该变量，并使用 scale_* 层调整颜色。
library(ggplot2)colpf <- c(0, 0, 0, 1, 1, 1, 2, 2, 2)coldf <- c(0, 1, 2, 0, 1, 2, 0, 1, 2)x <- seq(0, 8, 1)y <- seq(0, 8, 1)df <- data.frame(colpf, coldf, x, y)i <- with(df, colpf == 1 & coldf == 1)i#> [1] FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSEggplot(data = df) +geom_point(aes(x = x, y = y, color = i), show.legend = FALSE) +scale_color_manual(values = c(`FALSE` = "black", `TRUE` = "red"))
创建于2023-02-23，使用 reprex v2.0.2
英文:
Create an indicator variable telling if the condition is met. Map the color aesthetic to that variable and adjust the colors with a scale_* layer.
library(ggplot2)colpf <- c(0,0,0,1,1,1,2,2,2)coldf <- c(0,1,2,0,1,2,0,1,2)x <- seq(0,8,1)y <- seq(0,8,1)df <- data.frame(colpf,coldf,x,y)i <- with(df, colpf == 1 & coldf == 1)i#> [1] FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSEggplot(data = df) +geom_point(aes(x = x, y = y, color = i), show.legend = FALSE) +scale_color_manual(values = c(`FALSE` = "black", `TRUE` = "red"))
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<sup>Created on 2023-02-23 with reprex v2.0.2</sup>
答案2
得分: 1
尽管Rui Barradas的答案更加优雅，如果您不想进行条件判断或无法确定特定条件，一个替代方法是通过索引特定兴趣点来实现：
ggplot() +geom_point(data = df[-5,], aes(x = x, y = y), show.legend = FALSE) +geom_point(data = df[5,], aes(x = x, y = y), color = "red", show.legend = FALSE)
英文:
Although Rui Barradas's answer is more elegant, if you didn't want to condition or could not determine a specific condition an alternative is to do this by indexing the specific point of interest:
ggplot() +geom_point(data = df[-5,], aes(x = x, y = y), show.legend = FALSE) +geom_point(data = df[5,], aes(x = x, y = y), color = "red", show.legend = FALSE)
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