《ggplot2-EGDA》 -2.1-to-2.5

dsmall <- diamonds[sample(nrow(diamonds), 100), ]

qplot(carat, price, data = diamonds)

##1.基本aesthetic attributes :colour\shape\size\alpha

qplot(carat, price, data = dsmall, colour = color) 
qplot(carat, price, data = dsmall, shape = cut) 
qplot(carat, price, data = diamonds, alpha = I(1/10)) 
###You can also manually set the aesthetics using I() 

#####2.geometric object
###2.1 smooth method到底用什么方法 可以加载不同的包 如MASS 按相应的回归formula输入即可
qplot(carat, price, data = dsmall, geom = c("point", "smooth")) #####默认小样本（小于1000）使用局部回归
qplot(carat, price, data = dsmall, geom = c("point", "smooth"),span = 0.2) #span调整平滑程度 
library(mgcv)
qplot(carat, price, data = dsmall, geom = c("point", "smooth"),method = "gam", formula = y ~ s(x, bs = "cs")) #####默认大样本（大于1000）的回归算法
qplot(carat, price, data = dsmall, geom = c("point", "smooth"),method = "lm") #最小二乘

qplot(color, price / carat, data = diamonds, geom = "jitter",alpha = I(1 / 5)) #第一个参数是分类变量，第二个是连续变量
qplot(cut,price/carat,data=dsmall,geom=c(‘jitter‘,‘boxplot‘),alpha=I(0.5),colour=cut)##jitter boxplot 可以一起用
##boxplot中colour是外框线颜色，fill是填充颜色,size是线的粗细

qplot(carat, data = diamonds, geom = "histogram", binwidth = 0.01,xlim = c(0,3))
##histogram默认Y轴为频数

qplot(carat, data = diamonds, geom = "histogram", fill = color) #使用fill参数可以很快得到堆积柱形图

qplot(color, data = diamonds, geom = "bar", weight = carat) +scale_y_continuous("carat") 
#y轴不再是频数，而是对给定的weight求和，+号后面的代码是变坐标轴名称count为carat

year <- function(x) as.POSIXlt(x)$year + 1900  #as.POSIXlt(x)读取的日期（字符串） 转化为 “Date” 类型数据
qplot(unemploy / pop, uempmed, data = economics,geom = c("point", "path"))
qplot(unemploy / pop, uempmed, data = economics,geom = "path", colour =year(date)) + scale_size_area()  #按年份更换颜色