This article describes how to **display the last value of each line as a label** using the ggplot2 R package. Different solutions are provided using either the `ggrepel`

text labeling or the `ggplot2`

secondary axis functions.

Contents:

## Prerequisites

Required R packages:

`tidyverse`

: easy data manipulation and visualization`ggrepel`

: provides`geoms`

for ggplot2 to repel overlapping text labels:`geom_text_repel() and geom_label_repel()`

```
# Load required R packages
library(tidyverse)
library(ggrepel)
# Set ggplot2 default theme to theme_bw()
theme_set(theme_bw())
# Demo data
df <- tibble::tribble(
~Species, ~Petal.Length, ~Petal.Width, ~Sepal.Length, ~Sepal.Width,
"setosa", 1.462, 0.246, 5.006, 3.428,
"versicolor", 4.26, 1.326, 5.936, 2.77,
"virginica", 5.552, 2.026, 6.588, 2.974
)
df
```

```
## # A tibble: 3 x 5
## Species Petal.Length Petal.Width Sepal.Length Sepal.Width
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 setosa 1.46 0.246 5.01 3.43
## 2 versicolor 4.26 1.33 5.94 2.77
## 3 virginica 5.55 2.03 6.59 2.97
```

```
# Transform the data into long format
# Put Petal.Length to Sepal.Width in the same column
df_long <- df %>%
pivot_longer(
Petal.Length:Sepal.Width,
names_to = "variable", values_to = "value"
)
df_long
```

```
## # A tibble: 12 x 3
## Species variable value
## <chr> <chr> <dbl>
## 1 setosa Petal.Length 1.46
## 2 setosa Petal.Width 0.246
## 3 setosa Sepal.Length 5.01
## 4 setosa Sepal.Width 3.43
## 5 versicolor Petal.Length 4.26
## 6 versicolor Petal.Width 1.33
## # … with 6 more rows
```

## Using ggrepel to add labels to the line ends

### Examples for discrete x-axis

```
# Basic line plot
lp <- ggplot(df_long, aes(x = Species, y = value, group = variable)) +
geom_line(aes(color = variable)) +
geom_point() +
theme(legend.position = "top")
# Filter the last values and add onto the line plot
# Corresponds to the `virginica` species
data_ends <- df_long %>% filter(Species == "virginica")
lp +
geom_text_repel(
aes(label = value), data = data_ends,
fontface ="plain", color = "black", size = 3
)
```

```
# Use variable names as labels
lp2 <- ggplot(df_long, aes(x = Species, y = value, group = variable)) +
geom_line() +
geom_point()
lp2 +
geom_text_repel(
aes(label = variable), data = data_ends,
color = "black", size = 3
)
```

### Examples for time series data

```
# Demo data
df2 <- Orange
head(df2)
```

```
## Grouped Data: circumference ~ age | Tree
## Tree age circumference
## 1 1 118 30
## 2 1 484 58
## 3 1 664 87
## 4 1 1004 115
## 5 1 1231 120
## 6 1 1372 142
```

```
# Filter the last values
data_ends <- df2 %>%
group_by(Tree) %>%
top_n(1, age)
data_ends
```

```
## # A tibble: 5 x 3
## # Groups: Tree [5]
## Tree age circumference
## <ord> <dbl> <dbl>
## 1 1 1582 145
## 2 2 1582 203
## 3 3 1582 140
## 4 4 1582 214
## 5 5 1582 177
```

```
ggplot(df2, aes(age, circumference)) +
geom_line(aes(color = Tree)) +
geom_text_repel(
aes(label = circumference), data = data_ends,
size = 3
)
```

## Using a secondary y axis to show the line labels

Key R functions: The ggplot2 `scale_y_continuous()`

function is used in combination with the argument `sec.axis`

to create a second axis on the right. The numbers to be displayed at breaks is defined by the vector of values corresponding to the line ends.

```
# Pull the vector of last values
data_ends <- df2 %>%
group_by(Tree) %>%
top_n(1, age) %>%
pull(circumference)
data_ends
```

`## [1] 145 203 140 214 177`

```
# Create the line plot with labels
ggplot(df2, aes(x = age, y = circumference)) +
geom_line(aes(color = Tree)) +
scale_y_continuous(sec.axis = sec_axis(~ ., breaks = data_ends))
```

## Conclusion

This article describes how to display the last value of each line as a label.

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Version: Français

Good post, Kassambara – (as always!).

Question:

how to add BOTH the min and also the MAX values

at the end of each line?.

Thanks/Merci!

It is possible to add min-max values as follow: