Line break when no data in ggplot2

Question

I am using R to plot some data. ``` Date <- c("07/12/2012 05:00:00", "07/12/2012 06:00:00", "07/12/2012 07:00:00", "07/12/2012 08:00:00","07/12/2012 10:00:00","07/12/2012 11:00:00") Date <- strptime(Date, "%d/%m/%Y %H:%M") Counts <- c("0","3","10","6","5","4") Counts <- as.numeric(Counts) df1 <- data.frame(Date,Counts,stringsAsFactors = FALSE) library(ggplot2) g = ggplot(df1, aes(x=Date, y=Counts)) + geom_line(aes(group = 1)) g ``` How do I ask R not to plot data as a continuous line when there is a break in time? I normally have a data point every hour, but sometimes there is a break (between 8 am and 10 am). Between these points, I don't want the line to connect. Is this possible in R? Edit Many thanks for the responses here. My data is now in 10 second intervals, and I wish to do the same piece of analysis using this data. ``` df <- structure(list(Date = c("11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "…

Accepted Answer

You'll have to set `group` by setting a common value to those points you'd like to be connected. Here, you can set the first 4 values to say `1` and the last 2 to `2`. And keep them as factors. That is,

```
df1$grp <- factor(rep(1:2, c(4,2)))
g <- ggplot(df1, aes(x=Date, y=Counts)) + geom_line(aes(group = grp)) + 
                     geom_point()
```

Edit: Once you have your `data.frame` loaded, you can use this code to automatically generate the `grp` column:

```
idx <- c(1, diff(df$Date))
i2 <- c(1,which(idx != 1), nrow(df)+1)
df1$grp <- rep(1:length(diff(i2)), diff(i2))
```

Note: It is important to add `geom_point()` as well because if the `discontinuous range` happens to be the LAST entry in the data.frame, it won't be plotted (as there are not 2 points to connect the line). In this case, `geom_point()` will plot it.

As an example, I'll generate a data with more gaps:

```
# get a test data
set.seed(1234)
df <- data.frame(Date=seq(as.POSIXct("05:00", format="%H:%M"), 
                as.POSIXct("23:00", format="%H:%M"), by="hours"))
df$Counts <- sample(19)
df <- df[-c(4,7,17,18),]

# generate the groups automatically and plot
idx <- c(1, diff(df$Date))
i2 <- c(1,which(idx != 1), nrow(df)+1)
df$grp <- rep(1:length(diff(i2)), diff(i2))
g <- ggplot(df, aes(x=Date, y=Counts)) + geom_line(aes(group = grp)) + 
            geom_point()
g
```

Edit: For your NEW data (assuming it is `df`),

```
df$t <- strptime(paste(df$Date, df$Time), format="%d/%m/%Y %H:%M:%S")

idx <- c(10, diff(df$t))
i2 <- c(1,which(idx != 10), nrow(df)+1)
df$grp <- rep(1:length(diff(i2)), diff(i2))
```

now plot with `aes(x=t, ...)`.

Line break when no data in ggplot2

Solution

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