ggplot来自同一数据帧的多线图

Question

I have this dataframe (df) :

  day     time      value
20011101    93000 1.00000000
20011102    93000 1.00000000
20011105    93000 1.00000000
20011101   100000 0.81958763
20011102   100000 0.95412844
20011105   100000 0.27610209
20011101   103000 0.27835052
20011102   103000 0.32415902
20011105   103000 0.77958237
20011101   110000 0.23711340

Sample here: https://www.dropbox.com/s/y7mtcay6ke9ydnm/sample.txt

Using ggplot, I'm trying to get a line for every single day where axis x = time, so in RI wrote:

ggplot(df, aes(x=time, y=value, colour=day)) + geom_line()

Unfortunately, this is what I got. I did not expect a plot like this.

And this is an Excel graph. This is the one I'm looking for. A different line for every single day:

I do not know how to tell R to join dots from same day... What's wrong? What am I missing?

One more thing: As I have data from more than 5 years, I would prefer a one-color plot.

Thanks for your help!

Answer 1

添加group aes：

ggplot(df, aes(x=time, y=value, colour=day,group=day)) + geom_line()

Answer 2

Convert your day to a factor, it's being treated as continuous right now.

df$day <- as.factor(df$day)
ggplot(df, aes(x=time, y=value, colour=day)) + geom_line()