## Introduction

A line plot is a graph that connects multiple data points by making line segments between them. These points are ordered in one of their coordinate (usually the x-coordinate) values and are useful to investigate trends in our data set. In this tutorial, we are going to see how to create a line plot in R language with plot() function along with its syntax and various examples.

**Syntax plot() function for Line Plot in R**

Below is the basic syntax of plot() function for creating a line plot with some common parameters. For more details, you can check here.

*plot(v, type, main, sub, xlab, ylab, col)*

**x –**Represents the data to be plotted on x-axis**y –**Represents the data to be plotted on y-axis**type –**when the value is ‘l’ it draws line plot and when the value is ‘o’ or ‘b’ both line and point are drawn**main –**Represents the main title of the line plot**sub –**Represents the subtitle of the line plot**xlab –**Represents label of the x-axis of the line plot**ylab –**Represents label of the y-axis of the line plot

**Examples of Line Plot in R Language**

**Creating Sample Data**

Let us create a sample data that can be used in all the subsequent examples of line plot in R.

```
x <- 1:10
y <- c(3, 1, 5, 2, 3, 8, 4, 7, 6, 9)
```

**Example 1: Basic Line plot in R**

To draw a basic line plot in R, we use the plot function with the specification type = “l”.

Let us see the corresponding R code below:

```
plot(x,y, type = "l")
```

**Example 2: Add Main Title & Axis Labels of Line Plot**

To set the main title and the axis labels of the line plot we use main, xlab, and ylab arguments in the plot function as shown in the below example.

```
plot(x, y, type = "l",
main = "This is my Line Plot",
xlab = "My X-Values",
ylab = "My Y-Values")
```

**Example 3: Change Color of Line**

Let us now change the color of our line plot using the col argument in the plot function in the below example.

```
plot(x, y, type = "l",
col = "red", main = "This is my Line Plot",
xlab = "My X-Values",
ylab = "My Y-Values")
```

**Example 4: Control Line thickness**

We will now use the lwd option to modify our plot’s line thickness.

```
plot(x, y, type = "l",
col = "red", lwd=5, main = "This is my Line Plot",
xlab = "My X-Values",
ylab = "My Y-Values")
```

**Example 5: Line plot with Type = ‘s’**

It’s important to know that Besides type = “l”, there are a few more types of line plots available in base R. Setting type = “s” will create stair steps in the line plot as shown in the below example.

```
plot(x, y, type = "s", main = 'type = "s"',col = "brown", lwd=5)
```

**Example 6: Line plot with Type = ‘b’**

```
plot(x, y, type = "b", main = 'type = "b"',col = "green", lwd=5)
```

**Example 7: Line plot with Type = ‘o’**

```
plot(x, y, type = "b", main = 'type = "o"',col = "green", lwd=5)
```

**Example 8: Customize the points of Line plot with Letter**

In the example below we customize the points of the line plot in R with letters are passing the first five letters of the alphabet.

```
plot(x, y, type = "b",lwd=5,
pch = LETTERS[1:5], # Letters as symbols
cex = 2, # Size of the symbols
col = 1:5, # pch colors
xlim = c(1, 10), # X-axis limits
ylim = c(1, 10), main = "Customized Points Line Plot",
xlab = "My X-Values", ylab = "My Y-Values")
```

**Example 9: Customize the points of Line plot**

We can add the points separately to the line plot by using the points function, this allows us to customize the colors of the points as desired.

```
plot(x, y, type = "l", col = "red",lwd=5, main = "Customized Points in Line Plot",
xlab = "My X-Values",
ylab = "My Y-Values")
points(x, y,
pch = 21,
cex = 3,
bg = "green",
col = "blue",
lwd = 2)
```

**Example 10: Add Custom Annotation to Line plot**

In the below example, we add a custom annotation inside the plot by using the text function.

```
plot(x, y,, type = "l",lwd=5, col = "orange", main = "Custom Annotation Line Plot",
xlab = "My X-Values",
ylab = "My Y-Values")
text(x = 3, y =9, "This is my Custom annotation",cex=1.2)
```

**Example 11: Multiple Labels in Line plot**

To have multiple labels first, we will define the set of labels we wish to display. After this, we shall pass these labels into the text function along with the x and y coordinates, color, and size of the desired text label.

```
labels <- c("point 1", "point 2", "point 3", "point 4", "point 5")
plot(x, y, type = "l", lwd=5,col='darkblue',
xlim = c(1, 10), # X-axis limit
ylim = c(0,12), main = "Multiple texts Line Plot",
xlab = "My X-Values",
ylab = "My Y-Values") # Y-axis limit
text(x = x, y = y, labels, col = 'red',cex=1)
```

**Example 12: Plot multiple Line plots and add Legend**

To plot multiple lines to a graph in R. let us first create new variables for our line plot. Then we use the line function for creating two lines with their own customization of color.

```
y1 <- c(5, 1, 4, 6, 2, 3, 7, 8, 2, 8)
y2 <- c(3, 3, 3, 3, 4, 4, 5, 5, 7, 7)
```

```
plot(x, y,lwd=5, type = "l", main = "Multiple Line Plots",
xlab = "My X-Values",
ylab = "My Y-Values")
lines(x, y1, type = "l",lwd=5,, col = "purple")
lines(x, y2, type = "l",lwd=5, col = "blue")
legend("topleft", # Add legend to plot
legend = c("Line 1", "Line 2", "Line 3"),
col = c("black", "purple", "blue"),
lty = 1)
```