1) Since the times are dates be sure to use "Date"
class, not "POSIXct"
or "POSIXlt"
. See R News 4/1 for advice and try this where Lines
is defined in the Note at the end. No packages are used here.
dm <- read.table(text = Lines, header = TRUE)
dm$Date <- as.Date(dm$Date, "%m/%d/%Y")
plot(Visits ~ Date, dm, xaxt = "n", type = "l")
axis(1, dm$Date, format(dm$Date, "%b %d"), cex.axis = .7)
The use of text = Lines
is just to keep the example self-contained and in reality it would be replaced with something like "myfile.dat"
. (continued after image)
2) Since this is a time series you may wish to use a time series representation giving slightly simpler code:
library(zoo)
z <- read.zoo(text = Lines, header = TRUE, format = "%m/%d/%Y")
plot(z, xaxt = "n")
axis(1, dm$Date, format(dm$Date, "%b %d"), cex.axis = .7)
Depending on what you want the plot to look like it may be sufficient just to use plot(Visits ~ Date, dm)
in the first case or plot(z)
in the second case suppressing the axis
command entirely. It could also be done using xyplot.zoo
library(lattice)
xyplot(z)
or autoplot.zoo:
library(ggplot2)
autoplot(z)
Note:
Lines <- "Date Visits
11/1/2010 696537
11/2/2010 718748
11/3/2010 799355
11/4/2010 805800
11/5/2010 701262
11/6/2010 531579
11/7/2010 690068
11/8/2010 756947
11/9/2010 718757
11/10/2010 701768
11/11/2010 820113
11/12/2010 645259"
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