从R中的数据框绘制多行

Question

I have some data in a single dataframe. It represents several days' worth of data broken down by age within each day. What I'm looking to do is plot the Value (data points) for each age (y axis) by day (x axis). The frame is set up like this:

    Age day Value
1   13  15    139
2   14  15    198
3   15  15    287
4   16  15    404
5   17  15    439
6   18  15    323
7   19  15    255
8   13  16    135
9   14  16    202
10  15  16    309
11  16  16    380
12  17  16    451
13  18  16    366
14  19  16    256
15  13  17    117
16  14  17    208
17  15  17    303
18  16  17    392
19  17  17    410
20  18  17    359
21  19  17    246

Thus, 13 would plot from 139 to 135 to 117 over the three day period. I'm trying to use ggplot2, and am having trouble with the syntax. The end result should plot lines with different color by age.

So far I've tried this:

ggplot(d, aes(x=day, y=Age, color=Value, group=Age)) + geom_line()

But this yields an empty plot and this error message: geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?

What am I missing?

Answer 1

Not quite sure by your wording what you're after...

I think it's this...

ggplot(df, aes(day, Value, group=factor(Age), color=factor(Age))) + geom_line()

plots days vs Value with separate lines being each Age?