使用ggplot进行对数转换后如何将x轴设置为相同的比例

Question

数周以来，我一直在尝试解决一个看似简单的问题，同时使用 ggplot 绘制两个独立的直方图。因为数据不服从正态分布，所以我对它们进行对数转换。但是，我无法缩放设置独立图的 X 轴以显示完全相同的比例。

这是一个例子：

#random data:
set.seed(123); g1 <- data.frame(rlnorm(1000, 1, 3))
set.seed(123); g2 <- data.frame(rlnorm(2000, 0.4, 1.2))
colnames(g1) <- "value"; colnames(g2) <- "value"

#plotting g1 in logscale
plot_g1 <- ggplot(g1, aes(x=value)) + 
labs(x = "value", y = "Frequency") +
geom_density(alpha=0.25)+
theme_classic(base_size =25, base_line_size = 0.5)

plot_g1.2 <- ggplot(g1, aes(x=value)) + 
geom_histogram(binwidth=2.5, position = "identity", aes(y=..density..),  alpha = 0.75) +
labs(x = "value", y = "Frequency") +
geom_density(alpha=0.25)+
theme_classic(base_size = 10, base_line_size = 0.5)

plot_g1.2_log <- plot_g1.2 + 
scale_x_continuous(trans="log2", labels = scales::number_format(accuracy = 0.01, decimal.mark = '.'), breaks = c(0, 0.01, 0.1, 1, 10, 100, 10000), limits=c(-100, 20000))
[![plot_g1.2_log][1]][1]

绘图没问题，但每个 X 轴的比例不同。我玩过 limits、binwidth 和 breaks，但我无法让它工作。

一个解决方案是将两个分布绘制在一起：

###combining both plots together
g1$cat <- "g1"; g2$cat <- "g2" ; g12 <- rbind(g1,g2)

plot_g12 <- ggplot(g12, aes(x=value, fill = cat, color = cat)) + 
labs(x = "value", y = "Frequency") +
geom_density(alpha=0.25)+
theme_classic(base_size =10, base_line_size = 0.5)

plot_g12.2 <- ggplot(g12, aes(x=value, fill = cat, color = cat)) + 
geom_histogram(binwidth=0.5, position = "identity", aes(y=..density..),  alpha = 0.75) +
labs(x = "value", y = "Frequency") +
geom_density(alpha=0.25)+
theme_classic(base_size = 10, base_line_size = 0.5)

plot_g12.2_log <- plot_g12.2 + 
scale_x_continuous(trans="log2", labels = scales::number_format(accuracy = 0.01, decimal.mark = '.'), breaks = c(0, 0.01, 0.1, 1, 10, 100, 10000), limits=c(-10, 20000))
plot_g12.2_log

但我需要将它们分开。如果有人能帮助我，我将不胜感激。

最佳，

L

Answer 1

我认为您无法设置相同比例的原因是因为下限在 log-space 中无效，例如log2(-100) 的计算结果为 NaN。也就是说，您是否考虑过对数据进行分面？

library(ggplot2)

set.seed(123); g1 <- data.frame(rlnorm(1000, 1, 3))
set.seed(123); g2 <- data.frame(rlnorm(2000, 0.4, 1.2))
colnames(g1) <- "value"; colnames(g2) <- "value"

df <- rbind(
  cbind(g1, name = "G1"),
  cbind(g2, name = "G2")
)

ggplot(df, aes(value)) +
  geom_histogram(aes(y = after_stat(density)),
                 binwidth = 0.5) +
  geom_density() +
  scale_x_continuous(
    trans = "log2",
    labels = scales::number_format(accuracy = 0.01, decimal.mark = '.'),
    breaks = c(0, 0.01, 0.1, 1, 10, 100, 10000), limits=c(1e-3, 20000)) +
  facet_wrap(~ name)
#> Warning: Removed 4 rows containing non-finite values (stat_bin).
#> Warning: Removed 4 rows containing non-finite values (stat_density).
#> Warning: Removed 4 rows containing missing values (geom_bar).

^{由 reprex package (v1.0.0)}

于 2021 年 3 月 20 日创建

使用ggplot进行对数转换后如何将x轴设置为相同的比例

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