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    R语言 使用ggplot2绘制好看的分组散点图

    作者:shunshunshun18 栏目:未分类 时间:2021-04-01 14:43:11

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    我们以iris数据集为例,该数据集包括花萼的长度和宽度,花瓣的长度和宽度,以及物种,如下图:

    本文我们要绘制不同物种下花萼的长度和宽度的分布情况,以及二者之间的相关性关系。

    1. 首先载入ggplot2包,

    library(ggplot2)

    2. 然后进行ggplot(data = NULL, mapping = aes(), ..., environment = parent.frame())绘制,在绘制中第一个参数是数据,第二个参数是数据映射,是绘制的全局变量,其中包含的参数有x,y,color,size,alpha,shape等。

    例如:ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)),然后通过快捷散点绘制

    +geom_point(size = 2.0, shape = 16),颜色代表不同的物种,如下图:

    3. 上面显示的是最原始的散点绘制,通过颜色区分不同的物种,那么如何进行效果的提升呢?

    首先是可以进行分面,使得不同物种的对比效果更为显著,这里使用+facet_wrap( ~ Species),效果如下:

    4. 通过分面后对比效果好了不少,如果想看下不同物种下花萼长度与宽度的关系呢?可以使用+geom_smooth(method = "loess"),效果图如下:

    5. 通过上面的操作效果好了很多,但是还是感觉不够高大上,那我们可以使用library(ggthemes)这个包进行精修一下,通过修改theme,使用+theme_solarized(),效果如下:

    还有更多的theme选择,例如+theme_wsj(),效果如下:

    这样我们的图是不是高大上了很多呢,所以其实数据可视化也没有多难。最后给下源码:

    library(ggthemes)
    library(ggplot2)
    
    ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
     geom_point(size = 2.0, shape = 16) +
     facet_wrap( ~ Species) +
     geom_smooth(method = "loess")+
    
     theme_wsj()
    

    补充:R语言 画图神器ggplot2包

    ggplot2

    R语言里画图最好用的包啦。感觉图都挺清晰的,就懒得加文字了(或者以后回来补吧>.)前面几个图挺基础的,后面也许会有没见过的ggplot用法哦。

    Install Package

    install.packages("ggplot2")
    library(ggplot2)
    

    Scatter Plot

    为了方便展示,用gapminder的数据

    if(!require(gapminder)) install.packages("gapminder")
     library(gapminder)
    gapminder

    数据大概是这样的

    假设我们现在想要知道2007年lifeExp和人均GDP之间的关系。

    先筛选数据

    library(dplyr)
    gapminder_2007 <- gapminder %>%
     filter(year == 2007)

    画lifeExp和gdpPercap关系的散点图,x为gdpPercap,y为lifeExp。

    ggplot(gapminder_2007,aes(x = gdpPercap, y = lifeExp))+geom_point()

    看的出来lifeExp与gdpPercap存在近似lifeExp=log(gdpPercap)的关系,对x轴的数值进行log值处理。另外,为了呈现更多信息,用颜色标记国家所在的洲,并用点的大小表示人口数量。

    ggplot(gapminder_2007,aes(x = gdpPercap, y = lifeExp, color = continent, size = pop))+
     geom_point()+scale_x_log10()+theme_minimal()+
     labs(x = "GDP per capita",
     y = "Life expectancy",
     title = "Life expectancy increases as GDP per capita increases",
     caption = "Data source: gapminder")

    另外一种呈现方式如下:

    加入了回归线和坐标轴的histogram。

    plot <- ggplot(gapminder_2007, aes(x = gdpPercap, y = lifeExp)) + 
     geom_point()+geom_smooth(method="lm")+scale_x_log10()+
     labs(x = "GDP per capita",
     y = "Life expectancy",
     title = "Life expectancy increases as GDP per capita increases",
     caption = "Data source: gapminder")
    ggMarginal(plot, type = "histogram", fill="transparent")
    #ggMarginal(plot, type = "boxplot", fill="transparent")

    Histogram

    gapminder_gdp2007 <- gapminder %>%
     filter(year == 2007, continent == "Americas") %>%
     mutate(country = fct_reorder(country,gdpPercap,last))
    ggplot(gapminder_gdp2007, aes(x=country, y = gdpPercap))+
     geom_col(fill="skyblue", color="black")+
     labs(x = "Country",
     y = "GDP per capita",
     title = "GDP per capita in North America and South America, 2007",
     caption = "Data source: gapminder")+
     coord_flip()+theme_minimal()

    Line Plot

    gapminder_pop <- gapminder %>%
     filter(country %in% c("United States","China"))
    ggplot(gapminder_pop,aes(x = year, y = pop, color = country))+
     geom_line(lwd = 0.8)+theme_light()+
     labs(x = "Year",
     y = "Population",
     title = "Population in China and United States, 1953-2007",
     caption = "Data source: gapminder")

    Facet Plot

    gapminder_gdp <- gapminder %>%
     group_by(year, continent) %>%
     summarize(avg_gdp = mean(gdpPercap))
    ggplot(gapminder_gdp,aes(x = year, y = avg_gdp, color = continent))+
     geom_line(lwd = 0.8)+theme_light()+facet_wrap(~continent)+
     labs(x = "Year",
     y = "Average GDP per capita",
     title = "Average GDP per capita change in different continent",
     caption = "Data source: gapminder")+
     scale_x_continuous(breaks=c(1955,1970,1985,2000))

    Path Plot

    gapminder_lifeexp <- gapminder %>%
     filter(year %in% c(1957,2007), continent == "Europe") %>%
     arrange(year) %>%
     mutate(country = fct_reorder(country,lifeExp,last))
    ggplot(gapminder_lifeexp) +geom_path(aes(x = lifeExp, y = country),
     arrow = arrow(length = unit(1.5, "mm"), type = "closed")) +
     geom_text(
     aes(x = lifeExp,
     y = country,
     label = round(lifeExp, 1),
     hjust = ifelse(year == 2007,-0.2,1.2)),
     size =3,
     family = "Bookman",
     color = "gray25")+
     scale_x_continuous(limits=c(45, 85))+
     labs(
     x = "Life expectancy",
     y = "Country",
     title = "People live longer in 2007 compared to 1957",
     subtitle = "Life expectancy in European countries",
     caption = "Data source: gapminder"
     )
     

    Density Plot

    gapminder_1992 <- gapminder %>%
     filter(year == 1992)
    ggplot(gapminder_1992, aes(lifeExp))+theme_classic()+
     geom_density(aes(fill=factor(continent)), alpha=0.8) + 
     labs(
     x="Life expectancy",
     title="Life expectancy group by continent, 1992", 
     caption="Data source: gapminder",
     fill="Continent")

    Slope Chart

    gapminder_lifeexp2 <- gapminder %>%
     filter(year %in% c(1977,1987,1997,2007),
     country %in% c("Canada", "United States","Mexico","Haiti","El Salvador",
      "Guatemala","Jamaica")) %>%
     mutate(lifeExp = round(lifeExp))
    ylabs <- subset(gapminder_lifeexp2, year==head(year,1))$country
    yvals <- subset(gapminder_lifeexp2, year==head(year,1))$lifeExp
    ggplot(gapminder_lifeexp2, aes(x=as.factor(year),y=lifeExp)) +
     geom_line(aes(group=country),colour="grey80") +
     geom_point(colour="white",size=8) +
     geom_text(aes(label=lifeExp), size=3, color = "black") +
     scale_y_continuous(name="", breaks=yvals, labels=ylabs)+
     theme_classic()+
     labs(title="Life Expectancy of some North America countries change from 1977 to 2007") + 
     theme(axis.title=element_blank(),
     axis.ticks = element_blank(),
     plot.title = element_text(hjust=0.5))

    以上为个人经验,希望能给大家一个参考,也希望大家多多支持IIS7站长之家博文。如有错误或未考虑完全的地方,望不吝赐教。