# theme_test ggplot2 Theme in R (6 Examples)

This article demonstrates how to set the ggplot2 theme to the theme_test in R programming.

Youâ€™re here for the answer, so letâ€™s get straight to the examplesâ€¦

## Example Data & Packages

The following data will be used as basement for this tutorial:

```set.seed(122665)                           # Set random seed
data <- data.frame(x = rnorm(160),         # Create example data frame
y = rnorm(160),
group = LETTERS[1:4])

Table 1 shows that our example data consists of three columns.

In this tutorial, weâ€™ll also need to install and load the ggplot2 package:

```install.packages("ggplot2")                # Install & load ggplot2 package
library("ggplot2")```

## Example 1: Draw ggplot2 Scatterplot Using theme_test()

```ggplot(data,                               # theme_test scatterplot
aes(x = x,
y = y,
col = group)) +
geom_point() +
theme_test()```

## Example 2: Draw ggplot2 Density Plot Using theme_test()

```ggplot(data,                               # theme_test density plot
aes(x = x,
fill = group)) +
geom_density(alpha = 0.5) +
theme_test()```

## Example 3: Draw ggplot2 Histogram Using theme_test()

```ggplot(data,                               # theme_test histogram
aes(x = x,
fill = group)) +
geom_histogram(alpha = 0.5,
position = "identity",
bins = 50) +
theme_test()```

## Example 4: Draw ggplot2 Barchart Using theme_test()

```ggplot(aggregate(y ~ group, data, sum),    # theme_test barplot
aes(x = group,
y = y,
fill = group)) +
geom_bar(stat = "identity") +
theme_test()```

## Example 5: Draw ggplot2 Boxplot Using theme_test()

```ggplot(data,                               # theme_test boxplot
aes(x = x,
fill = group)) +
geom_boxplot() +
theme_test()```

## Example 6: Draw ggplot2 Line Plot Using theme_test()

```ggplot(data,                               # theme_test line plot
aes(x = x,
y = y,
col = group)) +
geom_line() +
theme_test()```

## Video & Further Resources

Would you like to know more about the ggplot2 package? Then you may have a look at the following video of my YouTube channel. I explain how to use the ggplot2 package in much more detail:

You can also find tutorials on how to plot different types of graphics such as xy-plots, density plots, bargraphs, boxplots, histograms, and line charts using other ggplot2 themes:

Also, you may check out the introductions to other add-on packages that provide extra themes for ggplot2 plots:

In addition, you may want to read some of the related articles on this website. You can find a selection of tutorials below.

To summarize: You have learned on this page how to apply the theme_test function to modify the design and layout of a ggplot2 plot in the R programming language. In case you have additional comments and/or questions, let me know in the comments section.

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