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nicholaspooran
Asked: 2024-08-03 13:53:26 +0800 CST

ggplot2 中的标签在添加文本标签时会错位点

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我正在尝试使用 R 中的 ggplot2 向散点图中的点添加文本标签。但是，添加文本标签后，与这些标签相关的点会错位。这是我的代码的简化版本：

library(ggplot2)
library(ggrepel)
library(dplyr)

df = data.frame(structure(list(FC = c(4.712, 4.8264, 0.078026, 0.098754, 11.612, 
0.21181, 6.1715, 0.15113, 0.19936, 0.23572, 0.23564, 6.9851, 
5.2465, 12.641, 4.4164, 0.24834, 7.4598, 5.1384, 0.18861, 0.24986
), log2FC = c(2.2363, 2.271, -3.6799, -3.34, 3.5375, -2.2391, 
2.6256, -2.7261, -2.3266, -2.0849, -2.0853, 2.8043, 2.3914, 3.6601, 
2.1429, -2.0096, 2.8991, 2.3613, -2.4065, -2.0008), Identifier = 1:20), row.names = c("3-Indoleacetic acid", 
"4-Hydroxyphenylpyruvic acid", "Adenine", "Adenosine", "alpha-Ketoglutaric acid", 
"C10", "C18:1OH", "Deoxyadenosine", "Deoxycytidine", "Deoxyguanosine", 
"Histamine", "Homocitrulline", "Indolelactic acid", "Kynurenine", 
"Leucine", "LysoPC a C20:4", "N-Acetylputrescine", "Phenylalanine", 
"Phenylethylamine", "Spermidine"), class = "data.frame"))


show.names = c("Kynurenine", "alpha-Ketoglutaric acid", "N-Acetylputrescine", "Homocitrulline", "C18:1OH", "Deoxycytidine", "Phenylethylamine", "Deoxyadenosine", "Adenosine", "Adenine")

p1 = ggplot(df, aes(x = Identifier, y = log2FC)) +
     geom_point(aes(color = log2FC >= 0)) +
     scale_color_manual(name = "Group", values = c("red", "blue"), labels = c("Down", "Up")) +
     geom_text_repel(data = df[rownames(df) %in% show.names,], aes(label = show.names)) +
     geom_hline(yintercept = 0, linetype = "solid") +
     labs(x = "Compounds", y = "Log2 Fold Change") + theme_minimal()
p1

输出

在生成的图中，点与标签未正确对齐。例如，“Kynurenine”具有正值（3.6601），但它们显示在图中的负值（接近 -4）区域

有人能帮助我理解为什么当我添加文本标签时点会放错位置，以及如何解决这个问题？

1 个回答

  1. Best Answer

    ggplot2 图中点和文本标签未对齐的问题似乎是由于 geom_text_repel 函数中标签的分配方式造成的。具体来说，show.names 向量未与数据框行直接对齐，导致文本标签放置错误。

    为了解决这个问题，您应该使用 geom_text_repel 中的标签美学并确保它根据名称正确匹配行。

    ggplot(df, aes(x = Identifier, y = log2FC)) +
     geom_point(aes(color = log2FC >= 0)) +
     scale_color_manual(name = "Group", values = c("red", "blue"), labels = c("Down", "Up")) +
     geom_text_repel(data = subset(df, rownames(df) %in% show.names), aes(label = rownames(subset(df, rownames(df) %in% show.names)))) +
     geom_hline(yintercept = 0, linetype = "solid") +
     labs(x = "Compounds", y = "Log2 Fold Change") + 
     theme_minimal()

    输出

    • 3

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