Question

我正在尝试使用循环通过ID号创建和保存单个图表。我不确定是否在执行错误的循环，或者它是否与数据设置有关。我最终得到的图上有两个ID的数据，但是根据ggsave命令定义的名称保存了两次。我觉得我缺少一些简单的东西。

我正在使用的数据是这样的：

df <- data.frame(ID = c(1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2), 
                   Time = c("1","2", "1", "2", "1", "2", "1", "2", "1", "2", "1", "2"), 
                   Category = c("Red", "Red", "Red", "Red", "Blue", "Blue", "Blue", "Blue", "Yellow","Yellow", "Yellow", "Yellow"), 
                   Score = c(0, 0, 0, 0, 1, 2, 0, 3, 1, 1, 3, 2))

这是我的代码：

idlist <-unique(df$ID)

for (i in idlist) {
  plot<- df %>%
    ggplot(aes(x=Category, y=as.numeric(Score), fill=Time))+
    geom_bar(color="black", stat="identity", position=position_dodge(.8), width=0.75)+
    geom_text(aes(x=Category, y=Score,label=Score), position=position_dodge(width=1), hjust=0.5, vjust=-.25, size=3)+
    labs(x="Category",y="Score")

  ggsave(filename=paste("plot",id[i],".png",sep=""), plot,
         device = function(...) png(..., units="in",res=200))
}

Answer 1

只需在循环中添加filter即可在当前循环的ID上构建图：

idlist <-unique(df$ID)

for (i in idlist) {
  plot <- df %>%
    filter(ID == i) %>%
    ggplot(aes(x=Category, y=as.numeric(Score), fill=Time)) +
    geom_bar(color="black", stat="identity", 
             position=position_dodge(.8), width=0.75) +
    geom_text(aes(x=Category, y=Score, label=Score), 
              position=position_dodge(width=1), hjust=0.5, vjust=-.25, size=3) +
    labs(x="Category", y="Score")

  ggsave(filename=paste("plot",  i, ".png", sep=""), plot,
         device = function(...) png(..., units="in", res=200))
}

或者，使用基数R的by并避免显式的for循环和unique()调用：

by(df, df$ID, function(sub) {
  plot <- ggplot(sub, aes(x=Category, y=as.numeric(Score), fill=Time)) +
            geom_bar(color="black", stat="identity", 
                     position=position_dodge(.8), width=0.75) +
            geom_text(aes(x=Category, y=Score, label=Score), 
                      position=position_dodge(width=1), hjust=0.5, vjust=-.25, size=3) +
            labs(x="Category", y="Score")

  ggsave(filename=paste0("plot", sub$id[[1]], ".png"), plot,
         device = function(...) png(..., units="in", res=200))
})

根据ID变量保存唯一的ggplots

1 个答案: