How to plot page views over time with qplot?

I have loaded a log onto a dataframe v. You can see the output of head(v):开发者_开发百科

  user_id    page_id           timestamp
1     139    1612783 2011-02-22 06:24:40
2     139    1612783 2011-02-22 06:28:40
3     139    1612783 2011-02-22 06:41:01

How can I qplot the number of page_id's per day?

• On the x-axis it would be the day (e.g. 2011-02-22).
• On the y-axis it would be the number of page_id's for that particular date.

---

This will work:

v <- data.frame(
          timestamp = as.Date(c("2011-02-22", "2011-02-22", "2011-02-23")), 
          page_id = c(1,2,1))
newdata <- data.frame(time=names(new), count=new)
qplot(time, page, data = newdata)

It is worth reading the ggplot manual, which has plenty of qplot examples, including times series.

---

t1 = with(v, table(as.Date(timestamp), page_id))
t2 = apply(t1 > 0, 1, sum)
dates = as.Date(names(t2))
plot(t2 ~ dates)                             # using plot
qplot(dates, t2, data=data.frame(t2, dates)) # using qplot

You can write this in a more compact form, but this way you can check the values of t1 and t2.