如何使用 plot 或 ggplot2 在 R 中快速绘制多条线

Question

I have a dataframe (see below) that has several lines more than shown labeled via the Fly column (each is unique) and a condition that each line received labeled via the condition column. Each line has four measurements associated with it taken at different times. I want to plot volume on the X as volume and Y as time. and color code by the unique line under Fly. Is there a quick and easy way to do this? Not to sure how to get this to work or started with ggplot2() or even plot(). Some help and guidance would be appreciated.

     Fly condition_1 volume_1 volume_2 volume_3 volume_4
1     1    postcont      1.6     18.0      8.1     13.5
2     2    postcont      0.0     12.0     10.1      8.5
3     3    postcont      2.6      3.0     10.1      1.5
4     4    postcont     13.6     13.0     10.1     15.5

Here is the code up to plotting

data1<-read.table(file=file.choose(),header=T)
head(data1)
postcontexp<-subset(data1, condition_1 == "postcont")
postcontexpVOL<- subset(# to remove unwanted columns)
postcontexpVOL<- na.omit(postcontexpVOL)

Answer 1

Here is a version using melt from reshape2 and dplyr to fit adjust the data:

n <- 4
df <-
  data.frame(
    Ind = 1:n
    , vol_1 = rnorm(n)
    , vol_2 = rnorm(n)
    , vol_3 = rnorm(n)
    , vol_4 = rnorm(n)
  )


melted <-
  melt(df, id.vars = "Ind") %>%
  mutate(Time = as.numeric(gsub("vol_","",variable)))

ggplot(melted
       , aes(x = Time
             , y = value
             , col = as.factor(Ind))) +
  geom_line()