##借出ggplot2，並查看功能
library(ggplot2)

?ggplot2

install.packages(“gapminder”)

#載入資料

library(gapminder)
##檢視資料
data(gapminder)
str(gapminder)
## Classes 'tbl_df', 'tbl' and 'data.frame':    1704 obs. of  6 variables:
##  $ country  : Factor w/ 142 levels "Afghanistan",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ continent: Factor w/ 5 levels "Africa","Americas",..: 3 3 3 3 3 3 3 3 3 3 ...
##  $ year     : int  1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 ...
##  $ lifeExp  : num  28.8 30.3 32 34 36.1 ...
##  $ pop      : int  8425333 9240934 10267083 11537966 13079460 14880372 12881816 13867957 16317921 22227415 ...
##  $ gdpPercap: num  779 821 853 836 740 ...
##gapminder存進gap
gap <- gapminder
##先設定x軸
ggplot(data = gap, aes(x = lifeExp))

##劃出直方圖
ggplot(data = gap, aes(x = lifeExp)) + 
    geom_histogram()
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

ggplot(data = gap, aes(x = lifeExp)) + 
  ##使用十個藍色長條
  geom_histogram(fill = "blue", color = "black", bins = 10) + 
  ##設定標題
  ggtitle("Life expectancy for the gap dataset") + 
  ##設定兩軸
  xlab("Life expectancy (years)") + 
  ylab("Frequency") + 
  ##設定主題
  theme_classic() 

## 定義x、y，依continent用不同的顏色表示
ggplot(data = gap, aes(x = continent, y = lifeExp, fill = continent)) + 
  geom_boxplot() + 
  ggtitle("Boxplots for lifeExp by continent") + 
  xlab("Continent") + 
  ylab("Life expectancy (years)") +
  ##設定標題，以及x、y軸名稱
  theme_minimal()

#設定主題

#+guides(fill = FALSE)

What happens if you un-hashtage guides(fill = FALSE) and the plus sign in lines 68 and 69 above?

取消圖例

## 定義x、y，依continent用不同的顏色、形狀表示
ggplot(data = gap, aes(x = lifeExp, y = gdpPercap, color = continent, shape = continent)) + 
    geom_point(size = 5, alpha = 0.5) + 
  ##點點的大小、透明度
    theme_classic() +
  ##設定主題
  
    ggtitle("Scatterplot of life expectancy by gdpPercap") +
    xlab("Life expectancy (years)") + 
    ylab("gdpPercap (USD)") + 
  ##設定標題，以及x、y軸名稱
  
    theme(legend.position = "top",
  ##把圖例移到最上方
          plot.title = element_text(hjust = 0.5, size = 20),
  ##設定標題大小和位置
          legend.title = element_text(size = 10),
  ##設定圖例標題大小
          legend.text = element_text(size = 10),
  ##設定圖例大小
          axis.text.x = element_text(angle = 45, hjust = 1)) 

##設定x軸數字的角度、位置

In lines the ggplot code above, what are the arguments inside of our second “theme” argument doing?

調整圖像的元素：標題、圖例、x軸

The End