1.
arrange用法:
按照变量管理行。
arrange(.data, ...)
data为要处理的列;...为要按照某变量排列,默认为升序排列。
> arrange(mtcars, cyl,disp) ##按照变量cyl, disp排序 mpg cyl disp hp drat wt qsec vs am gear carb1 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 12 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 23 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 14 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 15 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 26 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 17 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 18 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 29 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 210 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 211 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 212 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 613 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 414 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4
> arrange(mtcars, desc(disp)) ##按照disp变量降序排列 mpg cyl disp hp drat wt qsec vs am gear carb1 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 42 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 43 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 44 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 25 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 26 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 47 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 48 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 49 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 210 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2 2.
filter的用法:
filter(.data, ...)
.data为tbl类型的数据,所有的主要动词为S3类;...为传递的条件,多个条件之间用&连接。
> filter(mtcars, cyl == 8) ##提取mtcars数据中变量cyl为8的数据 mpg cyl disp hp drat wt qsec vs am gear carb1 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 22 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 43 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 34 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 35 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 36 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 47 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 48 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 49 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 210 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 211 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 412 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 213 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 414 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8
> filter(mtcars, cyl<6 | vs == 1) mpg cyl disp hp drat wt qsec vs am gear carb1 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 12 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 13 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 14 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 25 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 26 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 47 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 48 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 19 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 210 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 111 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 112 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 113 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 214 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 215 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2
> filter(mtcars, cyl<6 & vs == 1) mpg cyl disp hp drat wt qsec vs am gear carb1 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 12 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 23 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 24 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 15 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 26 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 17 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 18 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 19 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 210 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 3.
group_by的用法:
group_by(.data, ..., add = FALSE)
data为S3类型的tbl数据;... 为要分组的变量,也可为表达式; add为是否添加已存在的组,默认为覆盖。
> grouped <- group_by(mtcars, cyl) ##mtcars按照cyl分组> groupedSource: local data frame [32 x 11]Groups: cyl [3] mpg cyl disp hp drat wt qsec vs am* 1 21.0 6 160.0 110 3.90 2.620 16.46 0 12 21.0 6 160.0 110 3.90 2.875 17.02 0 13 22.8 4 108.0 93 3.85 2.320 18.61 1 14 21.4 6 258.0 110 3.08 3.215 19.44 1 05 18.7 8 360.0 175 3.15 3.440 17.02 0 06 18.1 6 225.0 105 2.76 3.460 20.22 1 07 14.3 8 360.0 245 3.21 3.570 15.84 0 08 24.4 4 146.7 62 3.69 3.190 20.00 1 09 22.8 4 140.8 95 3.92 3.150 22.90 1 010 19.2 6 167.6 123 3.92 3.440 18.30 1 0# ... with 22 more rows, and 2 more variables:# gear , carb
> summarise(grouped, mean(disp), mean(hp)) ##对分组变量分别求均值# A tibble: 3 × 3 cyl `mean(disp)` `mean(hp)` 1 4 105.1364 82.636362 6 183.3143 122.285713 8 353.1000 209.21429
> filter(grouped, disp == max(disp)) ##分别找出各自组中disp的最大值Source: local data frame [3 x 11]Groups: cyl [3] mpg cyl disp hp drat wt qsec vs am 1 21.4 6 258.0 110 3.08 3.215 19.44 1 02 24.4 4 146.7 62 3.69 3.190 20.00 1 03 10.4 8 472.0 205 2.93 5.250 17.98 0 0# ... with 2 more variables: gear , carb
> by_vs_am <- group_by(mtcars, vs, am) ##按照两个变量vs, am分组> by_vs_amSource: local data frame [32 x 11]Groups: vs, am [4] mpg cyl disp hp drat wt qsec vs am* 1 21.0 6 160.0 110 3.90 2.620 16.46 0 12 21.0 6 160.0 110 3.90 2.875 17.02 0 13 22.8 4 108.0 93 3.85 2.320 18.61 1 14 21.4 6 258.0 110 3.08 3.215 19.44 1 05 18.7 8 360.0 175 3.15 3.440 17.02 0 06 18.1 6 225.0 105 2.76 3.460 20.22 1 07 14.3 8 360.0 245 3.21 3.570 15.84 0 08 24.4 4 146.7 62 3.69 3.190 20.00 1 09 22.8 4 140.8 95 3.92 3.150 22.90 1 010 19.2 6 167.6 123 3.92 3.440 18.30 1 0# ... with 22 more rows, and 2 more variables:# gear , carb
> by_va <- summarise(by_vs_am, n = n()) ## 对分组变量进行计数,其中n()只应用于summarise, ##mutate和filter函数> by_vaSource: local data frame [4 x 3]Groups: vs [?] vs am n 1 0 0 122 0 1 63 1 0 74 1 1 7
> summarise(by_va, n = sum(n)) ##汇总计数,但是只对第一列# A tibble: 2 × 2 vs n 1 0 182 1 14
> group_by(mtcars, vsam = vs + am) ##分组变量为表达式,默认添加这一列Source: local data frame [32 x 12]Groups: vsam [3] mpg cyl disp hp drat wt qsec vs am 1 21.0 6 160.0 110 3.90 2.620 16.46 0 12 21.0 6 160.0 110 3.90 2.875 17.02 0 13 22.8 4 108.0 93 3.85 2.320 18.61 1 14 21.4 6 258.0 110 3.08 3.215 19.44 1 05 18.7 8 360.0 175 3.15 3.440 17.02 0 06 18.1 6 225.0 105 2.76 3.460 20.22 1 07 14.3 8 360.0 245 3.21 3.570 15.84 0 08 24.4 4 146.7 62 3.69 3.190 20.00 1 09 22.8 4 140.8 95 3.92 3.150 22.90 1 010 19.2 6 167.6 123 3.92 3.440 18.30 1 0# ... with 22 more rows, and 3 more variables:# gear , carb , vsam 4.
mutate和
transmute的用法:
mutate(.data, ... )
data为tbl类型数据;... 为融合的变量。
mutate和transmute的区别主要是mutate保持原有变量并新增加变量,而transmute只有新增加的变量。
> mutate(mtcars, displ_l = disp / 61.0237) mpg cyl disp hp drat wt qsec vs am gear carb displ_l1 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 2.6219322 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 2.6219323 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 1.7698044 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 4.2278665 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 5.8993476 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 3.6870927 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 5.8993478 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 2.4039849 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 2.30730010 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 2.746474............................................................................................................
> transmute(mtcars, displ_l = disp / 61.0237) displ_l1 2.6219322 2.6219323 1.7698044 4.2278665 5.8993476 3.6870927 5.8993478 2.4039849 2.30730010 2.746474......................
> mutate(mtcars, cyl = NULL) ##去掉cyl一列 mpg disp hp drat wt qsec vs am gear carb1 21.0 160.0 110 3.90 2.620 16.46 0 1 4 42 21.0 160.0 110 3.90 2.875 17.02 0 1 4 43 22.8 108.0 93 3.85 2.320 18.61 1 1 4 14 21.4 258.0 110 3.08 3.215 19.44 1 0 3 15 18.7 360.0 175 3.15 3.440 17.02 0 0 3 26 18.1 225.0 105 2.76 3.460 20.22 1 0 3 17 14.3 360.0 245 3.21 3.570 15.84 0 0 3 48 24.4 146.7 62 3.69 3.190 20.00 1 0 4 29 22.8 140.8 95 3.92 3.150 22.90 1 0 4 210 19.2 167.6 123 3.92 3.440 18.30 1 0 4 4.................................................................................................... 5.
nth,n_distinct的用法:
nth(x, n, order_by = NULL, default = default_missing(x))
x为一个向量;order_by为可选的决定顺序的变量。
> x <- 1:10> nth(x,4)[1] 4n_distinct(x, na_rm = FALSE)
x为数值向量。
n_distinct要比length(unique(x))更快更精确。
> x <- sample(1:10, 1e5, rep = T)> length(unique(x))[1] 10
> n_distinct(x)[1] 106.
sample_n的用法:
sample_n(tbl, size, replace = FALSE, weight = NULL, .env = parent.frame())
tbl为数据框;size为抽取行数,replace为是否可重复抽样; weight为权重,非负向量,自动转化权重和为1.
> by_cyl <- mtcars %>% group_by(cyl)> sample_n(mtcars, 10, weight = mpg) mpg cyl disp hp drat wt qsec vs am gearHonda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4
> sample_n(by_cyl, 3) ##对于分组的数据,是对每个组进行抽样Source: local data frame [9 x 11]Groups: cyl [3] mpg cyl disp hp drat wt qsec vs am gear 1 21.5 4 120.1 97 3.70 2.465 20.01 1 0 32 22.8 4 140.8 95 3.92 3.150 22.90 1 0 43 21.4 4 121.0 109 4.11 2.780 18.60 1 1 44 21.4 6 258.0 110 3.08 3.215 19.44 1 0 35 17.8 6 167.6 123 3.92 3.440 18.90 1 0 46 19.7 6 145.0 175 3.62 2.770 15.50 0 1 57 14.7 8 440.0 230 3.23 5.345 17.42 0 0 38 13.3 8 350.0 245 3.73 3.840 15.41 0 0 39 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5# ... with 1 more variables: carb 此文章是我首先发表在我的博客上
http://blog.sina.com.cn/s/blog_15dd753ab0102wv83.html
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