学习小组Day6笔记-菠萝

作者: 菠萝_c93e | 来源:发表于2020-03-18 18:48 被阅读0次

    R包

    1镜像设置

    options("repos" = c(CRAN="https://mirrors.tuna.tsinghua.edu.cn/CRAN/")) #对应清华源
    options(BioC_mirror="https://mirrors.ustc.edu.cn/bioc/") #对应中科大源
    

    2安装

    install.packages("ape") BiocManager::install("ape")

    3浏览

    library("ape") require("ape")

    4 ''dplyr''包

    新增列 mutate()

    > library(dplyr)
    > test <- iris[c(1:2,51:52,101:102),]
    > mutate(test, new = Sepal.Length * Sepal.Width)
      Sepal.Length Sepal.Width Petal.Length Petal.Width    Species   new
    1          5.1         3.5          1.4         0.2     setosa 17.85
    2          4.9         3.0          1.4         0.2     setosa 14.70
    3          7.0         3.2          4.7         1.4 versicolor 22.40
    4          6.4         3.2          4.5         1.5 versicolor 20.48
    5          6.3         3.3          6.0         2.5  virginica 20.79
    6          5.8         2.7          5.1         1.9  virginica 15.66
    

    筛选列 select()

    > select(test,c(1,3)) #按照列号筛选第1和3列
        Sepal.Length Petal.Length
    1            5.1          1.4
    2            4.9          1.4
    51           7.0          4.7
    52           6.4          4.5
    101          6.3          6.0
    102          5.8          5.1
    
    
    > select(test, Petal.Length, Species) #按照列筛选
        Petal.Length    Species
    1            1.4     setosa
    2            1.4     setosa
    51           4.7 versicolor
    52           4.5 versicolor
    101          6.0  virginica
    102          5.1  virginica
    
    

    筛选行 filter()

    > filter(test, Species %in% c("setosa","versicolor")&Sepal.Length > 5)
      Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
    1          5.1         3.5          1.4         0.2     setosa
    2          7.0         3.2          4.7         1.4 versicolor
    3          6.4         3.2          4.5         1.5 versicolor 
    

    按某1列或某几列对整个表格进行排序arrange()

    > arrange(test, desc(Petal.Width))   #用desc从大到小,默认为从小到大
      Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
    1          6.3         3.3          6.0         2.5  virginica
    2          5.8         2.7          5.1         1.9  virginica
    3          6.4         3.2          4.5         1.5 versicolor
    4          7.0         3.2          4.7         1.4 versicolor
    5          5.1         3.5          1.4         0.2     setosa
    6          4.9         3.0          1.4         0.2     setosa
    

    summarise() 汇总计算 count() 计数

    >group_by(test, Species)#根据species分组
    > summarise(group_by(test, Species),mean(Petal.Length), sd(Petal.Length),mean(Sepal.Width))#计算分组下的mean和sd
    # A tibble: 3 x 4
      Species    `mean(Petal.Length)` `sd(Petal.Length)` `mean(Sepal.Width)`
      <fct>                     <dbl>              <dbl>               <dbl>
    1 setosa                     1.4               0                    3.25
    2 versicolor                 4.6               0.141                3.2 
    3 virginica                  5.55              0.636                3   
    
    > count(test,Species) #统计species的unique值
    # A tibble: 3 x 2
      Species        n
      <fct>      <int>
    1 setosa         2
    2 versicolor     2
    3 virginica      2
    

    dplyr处理关系数据

    > inner_join(test1, test2, by = "x") #內连inner_join,取交集 
      x z y
    1 b A 2
    2 e B 5
    3 f C 6
    > left_join(test2, test1, by = 'x')   #左连left_join
      x y    z
    1 a 1 <NA>
    2 b 2    A
    3 c 3 <NA>
    4 d 4 <NA>
    5 e 5    B
    6 f 6    C
    > full_join( test1, test2, by = 'x')  #全连full_join
      x    z  y
    1 b    A  2
    2 e    B  5
    3 f    C  6
    4 x    D NA
    5 a <NA>  1
    6 c <NA>  3
    7 d <NA>  4
    > semi_join(x = test1, y = test2, by = 'x')  #半连接:返回能够与y表匹配的x表所有记录semi_join
      x z
    1 b A
    2 e B
    3 f C
    > anti_join(x = test2, y = test1, by = 'x')  #反连接:返回无法与y表匹配的x表的所记录anti_join
      x y
    1 a 1
    2 c 3
    3 d 4
    > test1 <- data.frame(x = c(1,2,3,4), y = c(10,20,30,40))
    > test2 <- data.frame(x = c(5,6), y = c(50,60))
    > test3 <- data.frame(z = c(100,200,300,400))
    > bind_rows(test1, test2)
      x  y
    1 1 10
    2 2 20
    3 3 30
    4 4 40
    5 5 50
    6 6 60
    > bind_cols(test1, test3)  #简单合并bind_rows()函数需要两个表格列数相同,而bind_cols()函数则需要两个数据框有相同的行数
      x  y   z
    1 1 10 100
    2 2 20 200
    3 3 30 300
    4 4 40 400
    

    相关文章

      网友评论

        本文标题:学习小组Day6笔记-菠萝

        本文链接:https://www.haomeiwen.com/subject/dainehtx.html