The **lines()** function is used to add lines to an existing plot in R.

The following method shows how you can do it with syntax.

**Method: Use lines() Function**

```
lines(x, y, col, lwd, lty)
```

x: Vector of x-coordinates y: Vector of y-coordinates col: Color of line lwd: Line width lty: Type of line

The following example shows how to use **lines()** function in R:

## Use lines() Function to Add Line in Plot

Let’s see how we can add line to plot using **lines()** function:

```
# Define x and y coordinate
Temperature <- c(71, 72, 73, 74, 75, 76)
Pressure <- c(11.23, 22.48, 33.78, 54.58, 65.25, 76.96)
# Create chart
plot(Temperature,Pressure)
# Define x and y coordinate for new line
Temperature <- c(70, 71.5, 72, 73, 73.5, 74)
Pressure <- c(11.80, 22.58, 23.78, 50.58, 61.25, 66.96)
# Create line
lines(Temperature,Pressure,col='red',lwd=6,lty="dashed")
```

Output:

In the above code we use **plot()** function to create scatter chart plot and then add new red line to plot using **lines()** function.