绘制多行数据框

Question

I have a data frame that looks like this:

Date          Something    Values
2013-01-01    A            1093
2013-01-01    B            123
2013-01-01    C            4352
2013-01-02    C            13
2013-01-02    B            768
2013-01-02    A            56
2013-01-03    A            37
2013-01-03    C            1033
2013-01-03    B            3
2013-01-04    A            5
....

I would like to plot "Date" on the X axis and "Values" on Y axis for each of "Something".

How can I do that in R?

Answer 1

Just write the following:

library(ggplot2)

a<-structure(list(Date = structure(c(15706, 15706, 15706, 15707, 
15707, 15707, 15708, 15708, 15708, 15709), class = "Date"), Something = structure(c(1L, 
2L, 3L, 3L, 2L, 1L, 1L, 3L, 2L, 1L), .Label = c("A", "B", "C"
), class = "factor"), Values = c(1093L, 123L, 4352L, 13L, 768L, 
56L, 37L, 1033L, 3L, 5L)), .Names = c("Date", "Something", "Values"
), row.names = c(NA, -10L), class = "data.frame")

ggplot(a, aes(x=Date, y=Values, color=Something, group=Something)) + geom_line()

where a is your data.frame according to your post. It will look something like:

Answer 2

If your intent is to plot a separate line(or character) for each subset on a single chart area, there are a variety of tricks with plyr you can use to organize your data in a useful way. For simplicity, here's a long way to do it.

Val_A<-dataframe[dataframe$Something=="A",]
Val_B<-dataframe[dataframe$Something=="B",]
Val_C<-dataframe[dataframe$Something=="C",]

(etc)

plot(Val_A$Date,Val_A$Values)
points(Val_B$Date,Val_B$Values,col='red')
points(Val_C$Date,Val_C$Values,col='green')

(etc)

As you can imagine, there are much more compact ways to do this.