Shredded Code

library(idbr) # devtools::install_github('walkerke/idbr')
library(ggplot2)
library(animation)
library(dplyr)
library(ggthemes)

idb_api_key("YOUR API CODE HERE")

male <- idb1('EZ', 2000:2050, sex = 'male') %>%
  mutate(POP = POP * -1,
         SEX = 'Male')

female <- idb1('EZ', 2000:2050, sex = 'female') %>%
  mutate(SEX = 'Female')

czechrep <- rbind(male, female) %>%
  mutate(abs_pop = abs(POP))

# Animate it with a for loop

saveGIF({
  
  for (i in 2000:2050) {
    
    title <- as.character(i)
    
    year_data <- filter(czechrep, time == i)
    
    g1 <- ggplot(year_data, aes(x = AGE, y = POP, fill = SEX, width = 1)) +
      coord_fixed() + 
      coord_flip() +
      geom_bar(data = subset(year_data, SEX == "Female"), stat = "identity") +
      geom_bar(data = subset(year_data, SEX == "Male"), stat = "identity") +
      scale_y_continuous(breaks = seq(-101000, 101000, 101000/2),
                         labels = paste0(as.character(c(seq(0.1, 0, -0.05), c(0.05, 0.1))), "m"), 
                         limits = c(min(czechrep$POP), max(czechrep$POP))) +
      theme_economist(base_size = 14) + 
      scale_fill_manual(values = c('#ff9896', '#d62728')) + 
      ggtitle(paste0('Population structure of Czech Republic, ', title)) + 
      ylab('Population') + 
      xlab('Age') + 
      theme(legend.position = "bottom", legend.title = element_blank()) + 
      guides(fill = guide_legend(reverse = TRUE))
    
    print(g1)
    
  }
  
}, movie.name = 'czechrep_pyramid.gif', interval = 0.1, ani.width = 700, ani.height = 600)