Global life expectancy: Line chart

Data

This plot uses the life_ex data frame of the gcubed package. This data frame contains life expectancy data for numerous countries and groups of countries in the Entity column.

library(gcubed)
head(life_ex)

## # A tibble: 6 x 4
##   Entity      Code   Year    LE
##   <chr>       <chr> <dbl> <dbl>
## 1 Afghanistan AFG    1950  27.5
## 2 Afghanistan AFG    1951  27.8
## 3 Afghanistan AFG    1952  28.4
## 4 Afghanistan AFG    1953  28.9
## 5 Afghanistan AFG    1954  29.4
## 6 Afghanistan AFG    1955  29.9

Code for plot

First, we will restrict the data set to only those rows that contain the life expectancy values for the country groups we are interested in. (Note that this filtering of rows could also have been done using base R.)

groups <- c("Upper-middle-income countries", "Middle-income countries", "Low-income countries",
  "Lower-middle-income countries","High-income countries")

library(dplyr)
df <- filter(life_ex, Entity %in% groups)
head(df)

## # A tibble: 6 x 4
##   Entity                Code   Year    LE
##   <chr>                 <chr> <dbl> <dbl>
## 1 High-income countries <NA>   1950  64.3
## 2 High-income countries <NA>   1951  64.6
## 3 High-income countries <NA>   1952  65.1
## 4 High-income countries <NA>   1953  65.5
## 5 High-income countries <NA>   1954  66.0
## 6 High-income countries <NA>   1955  66.4

The data is already in the correct shape to be used by geom_line: all the life expectancy values are in the single column, LE. To get different lines for each income group, the group aesthetic is used in the creation of the ggplot object. To give each line a different colour, the colour aesthetic is used.

library(ggplot2)

le_plt <- ggplot(df, aes(x = Year, y = LE, group = Entity, colour = Entity)) + 
  geom_line() + 
  ylab("Life Expectancy (Years)") + 
  ggtitle("Global Life Expectancy (1960 - 2015)") +
  theme(legend.title = element_blank())

le_plt

We can reorder the country groups so that the legend shows in the same order that the lines do in the plot.

library(ggplot2)
group_order <- c("High-income countries",  "Upper-middle-income countries", "Middle-income countries","Lower-middle-income countries", "Low-income countries")

df$Entity <- factor(df$Entity, levels = group_order)


le_plt <- ggplot(df, aes(x = Year, y = LE, group = Entity, colour = Entity)) + 
  geom_line() + 
  ylab("Life Expectancy (Years)") + 
  ggtitle("Global Life Expectancy (1960 - 2015)") +
  theme(legend.title = element_blank())

le_plt