我正在尝试使用multiplot在for循环中从ggplot每页编写多个绘图。但是，根据以下示例数据集，PDF仅在单独的页面上显示总共两个图（而不是四个）（而不是每页两个图）。
这就是我目前所拥有的：
> CohData
Name ScenID ScenName Year VarName Units value
1 Site01 0 Hind 2000 ANC ueq/L 35.34
2 Site01 1 BC 2020 ANC ueq/L 32.86
3 Site01 1 BC 2040 ANC ueq/L 32.25
4 Site02 0 Hind 2000 ANC ueq/L 28.23
5 Site02 1 BC 2020 ANC ueq/L 45.01
6 Site02 1 BC 2040 ANC ueq/L 57.86
7 Site01 0 Hind 2000 pH 5.93
8 Site01 1 BC 2020 pH 5.86
9 Site01 1 BC 2040 pH 5.85
10 Site02 0 Hind 2000 pH 6.40
11 Site02 1 BC 2020 pH 6.63
12 Site02 1 BC 2040 pH 6.75
library(ggplot2)
library(Rmisc)
## Iterate plots and write to PDF
pdf("plots.pdf")
CohData_nohind <- subset(CohData, ScenID > 0)
stream_vars <- list("ANC", "pH")
for (i in unique(CohData_nohind$ScenID)){
subdata1 <- subset(CohData_nohind, ScenID == i)
ScenName <- unique(subdata1$ScenName)
subdata1 <- subset(CohData, ScenID == i | ScenID == 0)
for (j in stream_vars){
subdata2 <- subset(subdata1, VarName == j)
units <- unique(subdata2$Units)
for (k in unique(subdata2$Name)){
subdata3 <- subset(subdata2, Name == k)
if (j=='ANC'){
plots <- list()
p <- ggplot(subdata3, aes(x = Year, y = value)) + geom_line() + expand_limits(y=c(0,100)) +
ggtitle(paste0(as.character(ScenName),":\n", as.character(k))) + ylab(paste0(j, " (", units, ")"))
plots[[i]] <- p
} else if (j=='pH'){
plots <- list()
p <- ggplot(subdata3, aes(x = Year, y = value)) + geom_line() + expand_limits(y=c(3,7)) +
ggtitle(paste0(as.character(ScenName),":\n", as.character(k))) + ylab(paste0(j, " (", units, ")"))
plots[[i]] <- p
}
}
multiplot(plotlist = plots, cols = 2)
}
}
dev.off()
完整数据集有五个“名称”，我希望每页有五个图（每个“名称”一个）。有任何建议吗？