第 37 章 tidyverse进阶
让我们继续聊聊，相见恨晚的tidyverse
37.1 scoped 函数
在第 12 章介绍了dplyr的一些函数（mutate(), select()等等），事实上，这些函数加上后缀
_all, _at, _if，形成三组变体函数，可以方便对特定的子集进行操作。比如
- 对数据框所有列操作，可以用
_all - 对数据框指定的几列操作，可以用
_at - 对数据框符合条件的几列进行操作，可以用
_if
下面选取其中几个函数加以说明
37.1.1 mutate_if
## # A tibble: 5 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <int> <int> <int> <int> <fct>
## 1 5 3 1 0 setosa
## 2 4 3 1 0 setosa
## 3 4 3 1 0 setosa
## 4 4 3 1 0 setosa
## 5 5 3 1 0 setosa可以一次性增加多列
## # A tibble: 5 × 13
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species Sepal.Length_fn1[,1]
## <dbl> <dbl> <dbl> <dbl> <fct> <dbl>
## 1 5.1 3.5 1.4 0.2 setosa 1.16
## 2 4.9 3 1.4 0.2 setosa 0.193
## 3 4.7 3.2 1.3 0.2 setosa -0.772
## 4 4.6 3.1 1.5 0.2 setosa -1.25
## 5 5 3.6 1.4 0.2 setosa 0.675
## # ℹ 7 more variables: Sepal.Width_fn1 <dbl[,1]>, Petal.Length_fn1 <dbl[,1]>,
## # Petal.Width_fn1 <dbl[,1]>, Sepal.Length_fn2 <dbl>, Sepal.Width_fn2 <dbl>,
## # Petal.Length_fn2 <dbl>, Petal.Width_fn2 <dbl>也可以把函数放在list()中，用 Purrr-style lambda 形式写出
## # A tibble: 5 × 13
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 5.1 3.5 1.4 0.2 setosa
## 2 4.9 3 1.4 0.2 setosa
## 3 4.7 3.2 1.3 0.2 setosa
## 4 4.6 3.1 1.5 0.2 setosa
## 5 5 3.6 1.4 0.2 setosa
## # ℹ 8 more variables: Sepal.Length_scale <dbl[,1]>,
## # Sepal.Width_scale <dbl[,1]>, Petal.Length_scale <dbl[,1]>,
## # Petal.Width_scale <dbl[,1]>, Sepal.Length_log <dbl>, Sepal.Width_log <dbl>,
## # Petal.Length_log <dbl>, Petal.Width_log <dbl>37.1.2 select_if()
## # A tibble: 3 × 3
## x y z
## <chr> <int> <dbl>
## 1 a 1 0
## 2 b 2 0
## 3 c 3 0## # A tibble: 3 × 2
## y z
## <int> <dbl>
## 1 1 0
## 2 2 0
## 3 3 0
df %>% select_if(~ n_distinct(.) > 2)## # A tibble: 3 × 2
## x y
## <chr> <int>
## 1 a 1
## 2 b 2
## 3 c 3select_if 多个条件的情况
df %>% select_if(
list(~ (is.numeric(.) | is.character(.)))
)## # A tibble: 3 × 3
## x y z
## <chr> <int> <dbl>
## 1 a 1 0
## 2 b 2 0
## 3 c 3 0
df %>% select_if(
~ (is.numeric(.) | is.character(.))
)## # A tibble: 3 × 3
## x y z
## <chr> <int> <dbl>
## 1 a 1 0
## 2 b 2 0
## 3 c 3 0
to_keep <- function(x) is.numeric(x) | is.character(x)
df %>% select_if(to_keep)## # A tibble: 3 × 3
## x y z
## <chr> <int> <dbl>
## 1 a 1 0
## 2 b 2 0
## 3 c 3 0
df %>% select_if(
list(~ (is.numeric(.) && sum(.) > 2))
)## # A tibble: 3 × 1
## y
## <int>
## 1 1
## 2 2
## 3 3
df %>% select_if(
list(~ (is.numeric(.) && mean(.) > 1))
)## # A tibble: 3 × 1
## y
## <int>
## 1 1
## 2 2
## 3 3我们也可以写成函数的形式
to_want <- function(x) is.numeric(x) && sum(x) > 3
df %>% select_if(to_want)## # A tibble: 3 × 1
## y
## <int>
## 1 1
## 2 2
## 3 337.2 summarise_if
msleep <- ggplot2::msleep
msleep %>%
dplyr::group_by(vore) %>%
dplyr::summarise_all(~ mean(., na.rm = TRUE))## # A tibble: 5 × 11
## vore name genus order conservation sleep_total sleep_rem sleep_cycle awake
## <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 carni NA NA NA NA 10.4 2.29 0.373 13.6
## 2 herbi NA NA NA NA 9.51 1.37 0.418 14.5
## 3 insecti NA NA NA NA 14.9 3.52 0.161 9.06
## 4 omni NA NA NA NA 10.9 1.96 0.592 13.1
## 5 <NA> NA NA NA NA 10.2 1.88 0.183 13.8
## # ℹ 2 more variables: brainwt <dbl>, bodywt <dbl>
msleep <- ggplot2::msleep
msleep %>%
dplyr::group_by(vore) %>%
# summarise_if(is.numeric, ~mean(., na.rm = TRUE))
dplyr::summarise_if(is.numeric, mean, na.rm = TRUE)## # A tibble: 5 × 7
## vore sleep_total sleep_rem sleep_cycle awake brainwt bodywt
## <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 carni 10.4 2.29 0.373 13.6 0.0793 90.8
## 2 herbi 9.51 1.37 0.418 14.5 0.622 367.
## 3 insecti 14.9 3.52 0.161 9.06 0.0216 12.9
## 4 omni 10.9 1.96 0.592 13.1 0.146 12.7
## 5 <NA> 10.2 1.88 0.183 13.8 0.00763 0.85837.3 filter_if()
事实上，filter已经很强大了，有了scoped函数，就如虎添翼了
msleep <- ggplot2::msleep
msleep %>%
dplyr::select(name, sleep_total) %>%
dplyr::filter(sleep_total > 18)## # A tibble: 4 × 2
## name sleep_total
## <chr> <dbl>
## 1 Big brown bat 19.7
## 2 Thick-tailed opposum 19.4
## 3 Little brown bat 19.9
## 4 Giant armadillo 18.1## # A tibble: 4 × 2
## name sleep_total
## <chr> <dbl>
## 1 Owl monkey 17
## 2 Long-nosed armadillo 17.4
## 3 North American Opossum 18
## 4 Arctic ground squirrel 16.6
msleep %>%
dplyr::select(name, sleep_total) %>%
# filter(near(sleep_total, 17, tol=sd(sleep_total)))
dplyr::filter(near(sleep_total, mean(sleep_total), tol = 0.5 * sd(sleep_total)))## # A tibble: 35 × 2
## name sleep_total
## <chr> <dbl>
## 1 Cheetah 12.1
## 2 Northern fur seal 8.7
## 3 Dog 10.1
## 4 Guinea pig 9.4
## 5 Grivet 10
## 6 Chinchilla 12.5
## 7 Star-nosed mole 10.3
## 8 African giant pouched rat 8.3
## 9 Lesser short-tailed shrew 9.1
## 10 European hedgehog 10.1
## # ℹ 25 more rowsmtcars是 R内置数据集，记录了32种不同品牌的轿车的的11个属性
## # A tibble: 32 × 11
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 6 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
## 7 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 8 24.4 4 147. 62 3.69 3.19 20 1 0 4 2
## 9 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2
## 10 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rowsfilter_if()配合all_vars(), any_vars()函数，可以完成很酷的工作.
比如，要求一行中所有变量的值都大于150
mtcars %>% filter_all(all_vars(. > 150))## # A tibble: 0 × 11
## # ℹ 11 variables: mpg <dbl>, cyl <dbl>, disp <dbl>, hp <dbl>, drat <dbl>,
## # wt <dbl>, qsec <dbl>, vs <dbl>, am <dbl>, gear <dbl>, carb <dbl>比如，要求一行中至少有一个变量的值都大于150
# Or the union:
mtcars %>% filter_all(any_vars(. > 150))## # A tibble: 21 × 11
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 4 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 5 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
## 6 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 7 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
## 8 17.8 6 168. 123 3.92 3.44 18.9 1 0 4 4
## 9 16.4 8 276. 180 3.07 4.07 17.4 0 0 3 3
## 10 17.3 8 276. 180 3.07 3.73 17.6 0 0 3 3
## # ℹ 11 more rows
# You can vary the selection of columns on which to apply the predicate.
# filter_at() takes a vars() specification:
mtcars %>% filter_at(vars(starts_with("d")), any_vars((. %% 2) == 0))## # A tibble: 13 × 11
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 6 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 7 10.4 8 472 205 2.93 5.25 18.0 0 0 3 4
## 8 10.4 8 460 215 3 5.42 17.8 0 0 3 4
## 9 14.7 8 440 230 3.23 5.34 17.4 0 0 3 4
## 10 15.5 8 318 150 2.76 3.52 16.9 0 0 3 2
## 11 15.2 8 304 150 3.15 3.44 17.3 0 0 3 2
## 12 13.3 8 350 245 3.73 3.84 15.4 0 0 3 4
## 13 19.2 8 400 175 3.08 3.84 17.0 0 0 3 2filter_if(.tbl, .predicate, .vars_predicate) 相对复杂点，我这里多说几句。
filter_if() 有三个参数：
- .tbl, 数据框
- .predicate, 应用在列上的函数，一般作为列的选择条件
- .vars_predicate, 应用在一行上的函数，通过
all_vars(), any_vars()返回值决定是否选取该行。
# And filter_if() selects variables with a predicate function:
# filter_if(.tbl, .predicate, .vars_predicate)
# mtcars %>% map_df(~ all(floor(.) == .) )
# mtcars %>% select_if( ~ all(floor(.) == .) )
mtcars %>% filter_if(~ all(floor(.) == .), all_vars(. != 0))## # A tibble: 7 × 11
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 2 32.4 4 78.7 66 4.08 2.2 19.5 1 1 4 1
## 3 30.4 4 75.7 52 4.93 1.62 18.5 1 1 4 2
## 4 33.9 4 71.1 65 4.22 1.84 19.9 1 1 4 1
## 5 27.3 4 79 66 4.08 1.94 18.9 1 1 4 1
## 6 30.4 4 95.1 113 3.77 1.51 16.9 1 1 5 2
## 7 21.4 4 121 109 4.11 2.78 18.6 1 1 4 2所以这里是，先通过.predicate = ~ all(floor(.) == .) 选取变量值为整数的列，然后再看选取的这些列的行方向，如果每一行的值.vars_predicate = all_vars(. != 0) ，都不为0，就保留下来，否则过滤掉。
简单点说，这段代码的意思，数值全部为整数的列，不能同时为0
37.4 group_by
group_by() 用的很多，所以要多讲讲
## # A tibble: 32 × 11
## # Groups: cyl [3]
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 6 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
## 7 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 8 24.4 4 147. 62 3.69 3.19 20 1 0 4 2
## 9 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2
## 10 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rows
mtcars %>% group_by_at(vars(cyl))## # A tibble: 32 × 11
## # Groups: cyl [3]
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 6 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
## 7 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 8 24.4 4 147. 62 3.69 3.19 20 1 0 4 2
## 9 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2
## 10 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rows
# Group a data frame by all variables:
mtcars %>% group_by_all()## # A tibble: 32 × 11
## # Groups: mpg, cyl, disp, hp, drat, wt, qsec, vs, am, gear, carb [32]
## mpg cyl disp hp drat wt qsec vs am gear carb
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 6 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
## 7 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 8 24.4 4 147. 62 3.69 3.19 20 1 0 4 2
## 9 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2
## 10 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rows
# Group by variables selected with a predicate:
iris %>% group_by_if(is.factor)## # A tibble: 150 × 5
## # Groups: Species [3]
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 5.1 3.5 1.4 0.2 setosa
## 2 4.9 3 1.4 0.2 setosa
## 3 4.7 3.2 1.3 0.2 setosa
## 4 4.6 3.1 1.5 0.2 setosa
## 5 5 3.6 1.4 0.2 setosa
## 6 5.4 3.9 1.7 0.4 setosa
## 7 4.6 3.4 1.4 0.3 setosa
## 8 5 3.4 1.5 0.2 setosa
## 9 4.4 2.9 1.4 0.2 setosa
## 10 4.9 3.1 1.5 0.1 setosa
## # ℹ 140 more rows37.4.1 group_split(), group_map(), group_modify()
iris %>%
dplyr::group_by(Species) %>%
dplyr::group_split()## <list_of<
## tbl_df<
## Sepal.Length: double
## Sepal.Width : double
## Petal.Length: double
## Petal.Width : double
## Species : factor<fb977>
## >
## >[3]>
## [[1]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 5.1 3.5 1.4 0.2 setosa
## 2 4.9 3 1.4 0.2 setosa
## 3 4.7 3.2 1.3 0.2 setosa
## 4 4.6 3.1 1.5 0.2 setosa
## 5 5 3.6 1.4 0.2 setosa
## 6 5.4 3.9 1.7 0.4 setosa
## 7 4.6 3.4 1.4 0.3 setosa
## 8 5 3.4 1.5 0.2 setosa
## 9 4.4 2.9 1.4 0.2 setosa
## 10 4.9 3.1 1.5 0.1 setosa
## # ℹ 40 more rows
##
## [[2]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 7 3.2 4.7 1.4 versicolor
## 2 6.4 3.2 4.5 1.5 versicolor
## 3 6.9 3.1 4.9 1.5 versicolor
## 4 5.5 2.3 4 1.3 versicolor
## 5 6.5 2.8 4.6 1.5 versicolor
## 6 5.7 2.8 4.5 1.3 versicolor
## 7 6.3 3.3 4.7 1.6 versicolor
## 8 4.9 2.4 3.3 1 versicolor
## 9 6.6 2.9 4.6 1.3 versicolor
## 10 5.2 2.7 3.9 1.4 versicolor
## # ℹ 40 more rows
##
## [[3]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 6.3 3.3 6 2.5 virginica
## 2 5.8 2.7 5.1 1.9 virginica
## 3 7.1 3 5.9 2.1 virginica
## 4 6.3 2.9 5.6 1.8 virginica
## 5 6.5 3 5.8 2.2 virginica
## 6 7.6 3 6.6 2.1 virginica
## 7 4.9 2.5 4.5 1.7 virginica
## 8 7.3 2.9 6.3 1.8 virginica
## 9 6.7 2.5 5.8 1.8 virginica
## 10 7.2 3.6 6.1 2.5 virginica
## # ℹ 40 more rows简单点写，就是
iris %>%
dplyr::group_split(Species)## <list_of<
## tbl_df<
## Sepal.Length: double
## Sepal.Width : double
## Petal.Length: double
## Petal.Width : double
## Species : factor<fb977>
## >
## >[3]>
## [[1]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 5.1 3.5 1.4 0.2 setosa
## 2 4.9 3 1.4 0.2 setosa
## 3 4.7 3.2 1.3 0.2 setosa
## 4 4.6 3.1 1.5 0.2 setosa
## 5 5 3.6 1.4 0.2 setosa
## 6 5.4 3.9 1.7 0.4 setosa
## 7 4.6 3.4 1.4 0.3 setosa
## 8 5 3.4 1.5 0.2 setosa
## 9 4.4 2.9 1.4 0.2 setosa
## 10 4.9 3.1 1.5 0.1 setosa
## # ℹ 40 more rows
##
## [[2]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 7 3.2 4.7 1.4 versicolor
## 2 6.4 3.2 4.5 1.5 versicolor
## 3 6.9 3.1 4.9 1.5 versicolor
## 4 5.5 2.3 4 1.3 versicolor
## 5 6.5 2.8 4.6 1.5 versicolor
## 6 5.7 2.8 4.5 1.3 versicolor
## 7 6.3 3.3 4.7 1.6 versicolor
## 8 4.9 2.4 3.3 1 versicolor
## 9 6.6 2.9 4.6 1.3 versicolor
## 10 5.2 2.7 3.9 1.4 versicolor
## # ℹ 40 more rows
##
## [[3]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 6.3 3.3 6 2.5 virginica
## 2 5.8 2.7 5.1 1.9 virginica
## 3 7.1 3 5.9 2.1 virginica
## 4 6.3 2.9 5.6 1.8 virginica
## 5 6.5 3 5.8 2.2 virginica
## 6 7.6 3 6.6 2.1 virginica
## 7 4.9 2.5 4.5 1.7 virginica
## 8 7.3 2.9 6.3 1.8 virginica
## 9 6.7 2.5 5.8 1.8 virginica
## 10 7.2 3.6 6.1 2.5 virginica
## # ℹ 40 more rows如果使用group_split(), 注意分组后，返回的是列表
iris %>%
dplyr::group_split(Species)## <list_of<
## tbl_df<
## Sepal.Length: double
## Sepal.Width : double
## Petal.Length: double
## Petal.Width : double
## Species : factor<fb977>
## >
## >[3]>
## [[1]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 5.1 3.5 1.4 0.2 setosa
## 2 4.9 3 1.4 0.2 setosa
## 3 4.7 3.2 1.3 0.2 setosa
## 4 4.6 3.1 1.5 0.2 setosa
## 5 5 3.6 1.4 0.2 setosa
## 6 5.4 3.9 1.7 0.4 setosa
## 7 4.6 3.4 1.4 0.3 setosa
## 8 5 3.4 1.5 0.2 setosa
## 9 4.4 2.9 1.4 0.2 setosa
## 10 4.9 3.1 1.5 0.1 setosa
## # ℹ 40 more rows
##
## [[2]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 7 3.2 4.7 1.4 versicolor
## 2 6.4 3.2 4.5 1.5 versicolor
## 3 6.9 3.1 4.9 1.5 versicolor
## 4 5.5 2.3 4 1.3 versicolor
## 5 6.5 2.8 4.6 1.5 versicolor
## 6 5.7 2.8 4.5 1.3 versicolor
## 7 6.3 3.3 4.7 1.6 versicolor
## 8 4.9 2.4 3.3 1 versicolor
## 9 6.6 2.9 4.6 1.3 versicolor
## 10 5.2 2.7 3.9 1.4 versicolor
## # ℹ 40 more rows
##
## [[3]]
## # A tibble: 50 × 5
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 6.3 3.3 6 2.5 virginica
## 2 5.8 2.7 5.1 1.9 virginica
## 3 7.1 3 5.9 2.1 virginica
## 4 6.3 2.9 5.6 1.8 virginica
## 5 6.5 3 5.8 2.2 virginica
## 6 7.6 3 6.6 2.1 virginica
## 7 4.9 2.5 4.5 1.7 virginica
## 8 7.3 2.9 6.3 1.8 virginica
## 9 6.7 2.5 5.8 1.8 virginica
## 10 7.2 3.6 6.1 2.5 virginica
## # ℹ 40 more rows既然是列表，当然想到用前面讲到的purrr::map()家族
iris %>%
dplyr::group_split(Species) %>%
purrr::map(~ broom::tidy(lm(Petal.Length ~ Sepal.Length, data = .x)))## [[1]]
## # A tibble: 2 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.803 0.344 2.34 0.0238
## 2 Sepal.Length 0.132 0.0685 1.92 0.0607
##
## [[2]]
## # A tibble: 2 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.185 0.514 0.360 7.20e- 1
## 2 Sepal.Length 0.686 0.0863 7.95 2.59e-10
##
## [[3]]
## # A tibble: 2 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.610 0.417 1.46 1.50e- 1
## 2 Sepal.Length 0.750 0.0630 11.9 6.30e-16
iris %>%
dplyr::group_split(Species) %>%
purrr::map_df(~ broom::tidy(lm(Petal.Length ~ Sepal.Length, data = .x)))## # A tibble: 6 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.803 0.344 2.34 2.38e- 2
## 2 Sepal.Length 0.132 0.0685 1.92 6.07e- 2
## 3 (Intercept) 0.185 0.514 0.360 7.20e- 1
## 4 Sepal.Length 0.686 0.0863 7.95 2.59e-10
## 5 (Intercept) 0.610 0.417 1.46 1.50e- 1
## 6 Sepal.Length 0.750 0.0630 11.9 6.30e-16上面这个代码，数据框分割成list, 处理完后再合并成数据框，难道不觉得折腾么？ 为什么直接点？
tidyverse不会让我们失望的，先看看group_map()
iris %>%
dplyr::group_by(Species) %>%
dplyr::group_map(~ broom::tidy(lm(Petal.Length ~ Sepal.Length, data = .x)))## [[1]]
## # A tibble: 2 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.803 0.344 2.34 0.0238
## 2 Sepal.Length 0.132 0.0685 1.92 0.0607
##
## [[2]]
## # A tibble: 2 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.185 0.514 0.360 7.20e- 1
## 2 Sepal.Length 0.686 0.0863 7.95 2.59e-10
##
## [[3]]
## # A tibble: 2 × 5
## term estimate std.error statistic p.value
## <chr> <dbl> <dbl> <dbl> <dbl>
## 1 (Intercept) 0.610 0.417 1.46 1.50e- 1
## 2 Sepal.Length 0.750 0.0630 11.9 6.30e-16-
group_map()要求 The result of .f should be a data frame(.f 必须返回数据框) -
group_map()return a list of tibble(返回元素均为df的一个列表list(df1,df2,df3))
数据框进来，然后分组，依次处理成一个个数据框，最后以列表形式（a list of tibble）输出。
事实上，group_map()是返回list形式，也就是说，可以是返回任何形式，（a list of tibble）是其中特殊形式。 可以看看下面这个
iris %>%
dplyr::group_by(Species) %>%
dplyr::group_map(
~ lm(Petal.Length ~ Sepal.Length, data = .x)
)## [[1]]
##
## Call:
## lm(formula = Petal.Length ~ Sepal.Length, data = .x)
##
## Coefficients:
## (Intercept) Sepal.Length
## 0.8031 0.1316
##
##
## [[2]]
##
## Call:
## lm(formula = Petal.Length ~ Sepal.Length, data = .x)
##
## Coefficients:
## (Intercept) Sepal.Length
## 0.1851 0.6865
##
##
## [[3]]
##
## Call:
## lm(formula = Petal.Length ~ Sepal.Length, data = .x)
##
## Coefficients:
## (Intercept) Sepal.Length
## 0.6105 0.7501group_modify() 才是真正意义上的”数据框进、数据框出”。
iris %>%
dplyr::group_by(Species) %>%
dplyr::group_modify(~ broom::tidy(lm(Petal.Length ~ Sepal.Length, data = .x)))## # A tibble: 6 × 6
## # Groups: Species [3]
## Species term estimate std.error statistic p.value
## <fct> <chr> <dbl> <dbl> <dbl> <dbl>
## 1 setosa (Intercept) 0.803 0.344 2.34 2.38e- 2
## 2 setosa Sepal.Length 0.132 0.0685 1.92 6.07e- 2
## 3 versicolor (Intercept) 0.185 0.514 0.360 7.20e- 1
## 4 versicolor Sepal.Length 0.686 0.0863 7.95 2.59e-10
## 5 virginica (Intercept) 0.610 0.417 1.46 1.50e- 1
## 6 virginica Sepal.Length 0.750 0.0630 11.9 6.30e-16为了大家方便查阅和记忆，我总结下表
| 函数 | 说明 | 常用组合 | 返回值 | 要求 |
|---|---|---|---|---|
| map() | 列表进、列表出 | df %>% group_split() %>% map() |
list | |
| map_df() | 列表进、数据框出 | df %>% group_split() %>% map_df() |
df | |
| group_map() | 数据框进、列表出 | df %>% group_by() %>% group_map() |
返回list(list1, list2, …) 特例list(df1, df2, …) |
|
| group_modify() | 数据框进、数据框出 | df %>% group_by() %>% group_modify() |
返回grouped tibble | .f返回df |
| walk | 列表进 | df %>% group_split() %>% walk() |
side effects | |
| group_walk() | 数据框进 | df %>% group_by() %>% group_walk() |
side effects |
我常用的批量出图的语句
nobel_winners %>%
dplyr::group_split(category) %>%
purrr::map(
~ ggplot(data = .x, aes(x = prize_age)) +
geom_density() +
ggtitle(.x$category)
)37.5 列名清理
数据框的列名，不要用有空格和中文。
如果拿到的原始数据中列比较多，手动修改麻烦，可以使用janitor::clean_names()函数
##
## Attaching package: 'janitor'## The following objects are masked from 'package:stats':
##
## chisq.test, fisher.test
roster_raw <- read_excel(here::here("demo_data", "dirty_data.xlsx"))## New names:
## • `Certification` -> `Certification...9`
## • `Certification` -> `Certification...10`
## • `Certification` -> `Certification...11`
glimpse(roster_raw)## Rows: 13
## Columns: 11
## $ `First Name` <chr> "Jason", "Jason", "Alicia", "Ada", "Desus", "Chien…
## $ `Last Name` <chr> "Bourne", "Bourne", "Keys", "Lovelace", "Nice", "W…
## $ `Employee Status` <chr> "Teacher", "Teacher", "Teacher", "Teacher", "Admin…
## $ Subject <chr> "PE", "Drafting", "Music", NA, "Dean", "Physics", …
## $ `Hire Date` <dbl> 39690, 39690, 37118, 27515, 41431, 11037, 11037, N…
## $ `% Allocated` <dbl> 0.75, 0.25, 1.00, 1.00, 1.00, 0.50, 0.50, NA, 0.50…
## $ `Full time?` <chr> "Yes", "Yes", "Yes", "Yes", "Yes", "Yes", "Yes", N…
## $ `do not edit! --->` <lgl> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA
## $ Certification...9 <chr> "Physical ed", "Physical ed", "Instr. music", "PEN…
## $ Certification...10 <chr> "Theater", "Theater", "Vocal music", "Computers", …
## $ Certification...11 <lgl> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA
roster <- roster_raw %>%
janitor::clean_names()
glimpse(roster)## Rows: 13
## Columns: 11
## $ first_name <chr> "Jason", "Jason", "Alicia", "Ada", "Desus", "Chien-S…
## $ last_name <chr> "Bourne", "Bourne", "Keys", "Lovelace", "Nice", "Wu"…
## $ employee_status <chr> "Teacher", "Teacher", "Teacher", "Teacher", "Adminis…
## $ subject <chr> "PE", "Drafting", "Music", NA, "Dean", "Physics", "C…
## $ hire_date <dbl> 39690, 39690, 37118, 27515, 41431, 11037, 11037, NA,…
## $ percent_allocated <dbl> 0.75, 0.25, 1.00, 1.00, 1.00, 0.50, 0.50, NA, 0.50, …
## $ full_time <chr> "Yes", "Yes", "Yes", "Yes", "Yes", "Yes", "Yes", NA,…
## $ do_not_edit <lgl> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA
## $ certification_9 <chr> "Physical ed", "Physical ed", "Instr. music", "PENDI…
## $ certification_10 <chr> "Theater", "Theater", "Vocal music", "Computers", NA…
## $ certification_11 <lgl> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA37.6 缺失值检查与处理
37.6.1 purrr & dplyr 技巧
## $Ozone
## [1] 37
##
## $Solar.R
## [1] 7
##
## $Wind
## [1] 0
##
## $Temp
## [1] 0
##
## $Month
## [1] 0
##
## $Day
## [1] 0## # A tibble: 1 × 6
## Ozone Solar.R Wind Temp Month Day
## <int> <int> <int> <int> <int> <int>
## 1 37 7 0 0 0 0
airquality %>%
dplyr::summarise_at(2:3, ~ sum(is.na(.)))## # A tibble: 1 × 2
## Solar.R Wind
## <int> <int>
## 1 7 037.6.2 缺失值替换
airquality %>%
mutate_all(funs(replace(., is.na(.), 0)))## # A tibble: 153 × 6
## Ozone Solar.R Wind Temp Month Day
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 41 190 7.4 67 5 1
## 2 36 118 8 72 5 2
## 3 12 149 12.6 74 5 3
## 4 18 313 11.5 62 5 4
## 5 0 0 14.3 56 5 5
## 6 28 0 14.9 66 5 6
## 7 23 299 8.6 65 5 7
## 8 19 99 13.8 59 5 8
## 9 8 19 20.1 61 5 9
## 10 0 194 8.6 69 5 10
## # ℹ 143 more rows
airquality %>%
mutate_all(replace_na, replace = 0)## # A tibble: 153 × 6
## Ozone Solar.R Wind Temp Month Day
## <int> <int> <dbl> <int> <int> <int>
## 1 41 190 7.4 67 5 1
## 2 36 118 8 72 5 2
## 3 12 149 12.6 74 5 3
## 4 18 313 11.5 62 5 4
## 5 0 0 14.3 56 5 5
## 6 28 0 14.9 66 5 6
## 7 23 299 8.6 65 5 7
## 8 19 99 13.8 59 5 8
## 9 8 19 20.1 61 5 9
## 10 0 194 8.6 69 5 10
## # ℹ 143 more rows## # A tibble: 153 × 6
## Ozone Solar.R Wind Temp Month Day
## <int> <int> <dbl> <int> <int> <int>
## 1 41 190 7.4 67 5 1
## 2 36 118 8 72 5 2
## 3 12 149 12.6 74 5 3
## 4 18 313 11.5 62 5 4
## 5 0 0 14.3 56 5 5
## 6 28 0 14.9 66 5 6
## 7 23 299 8.6 65 5 7
## 8 19 99 13.8 59 5 8
## 9 8 19 20.1 61 5 9
## 10 0 194 8.6 69 5 10
## # ℹ 143 more rows
airquality %>%
mutate_all(as.numeric) %>%
mutate_all(~ coalesce(., 0))## # A tibble: 153 × 6
## Ozone Solar.R Wind Temp Month Day
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 41 190 7.4 67 5 1
## 2 36 118 8 72 5 2
## 3 12 149 12.6 74 5 3
## 4 18 313 11.5 62 5 4
## 5 0 0 14.3 56 5 5
## 6 28 0 14.9 66 5 6
## 7 23 299 8.6 65 5 7
## 8 19 99 13.8 59 5 8
## 9 8 19 20.1 61 5 9
## 10 0 194 8.6 69 5 10
## # ℹ 143 more rows## # A tibble: 5 × 2
## y z
## <dbl> <dbl>
## 1 1 0
## 2 2 0
## 3 0 3
## 4 0 4
## 5 5 537.7 标准化
数据变量，在标准化之前是有单位的，如mm,kg等，标准之后就没有量纲了，而是偏离均值的程度，一般用多少方差，几个方差来度量。 标准化的好处在于，不同量纲的变量可以比较分析。
df_mtcars## # A tibble: 32 × 12
## rowname mpg cyl disp hp drat wt qsec vs am gear carb
## <chr> <dbl> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <fct> <fct> <fct> <fct>
## 1 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
## 2 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
## 3 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
## 4 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
## 5 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
## 6 6 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
## 7 7 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
## 8 8 24.4 4 147. 62 3.69 3.19 20 1 0 4 2
## 9 9 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2
## 10 10 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rows## Warning: `funs()` was deprecated in dplyr 0.8.0.
## ℹ Please use a list of either functions or lambdas:
##
## # Simple named list: list(mean = mean, median = median)
##
## # Auto named with `tibble::lst()`: tibble::lst(mean, median)
##
## # Using lambdas list(~ mean(., trim = .2), ~ median(., na.rm = TRUE))
## Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
## generated.## # A tibble: 32 × 6
## mpg disp hp drat wt qsec
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 21 160 110 3.9 2.62 16.5
## 2 21 160 110 3.9 2.88 17.0
## 3 22.8 108 93 3.85 2.32 18.6
## 4 21.4 258 110 3.08 3.22 19.4
## 5 18.7 360 175 3.15 3.44 17.0
## 6 18.1 225 105 2.76 3.46 20.2
## 7 14.3 360 245 3.21 3.57 15.8
## 8 24.4 147. 62 3.69 3.19 20
## 9 22.8 141. 95 3.92 3.15 22.9
## 10 19.2 168. 123 3.92 3.44 18.3
## # ℹ 22 more rows## # A tibble: 32 × 12
## rowname mpg[,1] cyl disp[,1] hp drat wt qsec vs am gear
## <chr> <dbl> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <fct> <fct> <fct>
## 1 1 0.151 6 -0.571 110 3.9 2.62 16.5 0 1 4
## 2 2 0.151 6 -0.571 110 3.9 2.88 17.0 0 1 4
## 3 3 0.450 4 -0.990 93 3.85 2.32 18.6 1 1 4
## 4 4 0.217 6 0.220 110 3.08 3.22 19.4 1 0 3
## 5 5 -0.231 8 1.04 175 3.15 3.44 17.0 0 0 3
## 6 6 -0.330 6 -0.0462 105 2.76 3.46 20.2 1 0 3
## 7 7 -0.961 8 1.04 245 3.21 3.57 15.8 0 0 3
## 8 8 0.715 4 -0.678 62 3.69 3.19 20 1 0 4
## 9 9 0.450 4 -0.726 95 3.92 3.15 22.9 1 0 4
## 10 10 -0.148 6 -0.509 123 3.92 3.44 18.3 1 0 4
## # ℹ 22 more rows
## # ℹ 1 more variable: carb <fct>## Warning: `funs()` was deprecated in dplyr 0.8.0.
## ℹ Please use a list of either functions or lambdas:
##
## # Simple named list: list(mean = mean, median = median)
##
## # Auto named with `tibble::lst()`: tibble::lst(mean, median)
##
## # Using lambdas list(~ mean(., trim = .2), ~ median(., na.rm = TRUE))
## Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
## generated.## # A tibble: 32 × 12
## rowname mpg cyl disp hp drat wt qsec vs am gear carb
## <chr> <dbl> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <fct> <fct> <fct> <fct>
## 1 1 0.151 6 -0.571 110 3.9 2.62 16.5 0 1 4 4
## 2 2 0.151 6 -0.571 110 3.9 2.88 17.0 0 1 4 4
## 3 3 0.450 4 -0.990 93 3.85 2.32 18.6 1 1 4 1
## 4 4 0.217 6 0.220 110 3.08 3.22 19.4 1 0 3 1
## 5 5 -0.231 8 1.04 175 3.15 3.44 17.0 0 0 3 2
## 6 6 -0.330 6 -0.0462 105 2.76 3.46 20.2 1 0 3 1
## 7 7 -0.961 8 1.04 245 3.21 3.57 15.8 0 0 3 4
## 8 8 0.715 4 -0.678 62 3.69 3.19 20 1 0 4 2
## 9 9 0.450 4 -0.726 95 3.92 3.15 22.9 1 0 4 2
## 10 10 -0.148 6 -0.509 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rows
# way 3
func <- function(x) (x - min(x)) / (max(x) - min(x))
df_mtcars %>%
mutate_at(vars(mpg, disp), ~ func(.))## # A tibble: 32 × 12
## rowname mpg cyl disp hp drat wt qsec vs am gear carb
## <chr> <dbl> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <fct> <fct> <fct> <fct>
## 1 1 0.451 6 0.222 110 3.9 2.62 16.5 0 1 4 4
## 2 2 0.451 6 0.222 110 3.9 2.88 17.0 0 1 4 4
## 3 3 0.528 4 0.0920 93 3.85 2.32 18.6 1 1 4 1
## 4 4 0.468 6 0.466 110 3.08 3.22 19.4 1 0 3 1
## 5 5 0.353 8 0.721 175 3.15 3.44 17.0 0 0 3 2
## 6 6 0.328 6 0.384 105 2.76 3.46 20.2 1 0 3 1
## 7 7 0.166 8 0.721 245 3.21 3.57 15.8 0 0 3 4
## 8 8 0.596 4 0.189 62 3.69 3.19 20 1 0 4 2
## 9 9 0.528 4 0.174 95 3.92 3.15 22.9 1 0 4 2
## 10 10 0.374 6 0.241 123 3.92 3.44 18.3 1 0 4 4
## # ℹ 22 more rows如果所有的列，都是数值型
func <- function(x) (x - min(x)) / (max(x) - min(x))
df_mtcars %>% mutate_all(~ func(.))## Error in `mutate()`:
## ℹ In argument: `rowname = (structure(function (..., .x = ..1, .y = ..2,
## . = ..1) ...`.
## Caused by error in `x - min(x)`:
## ! non-numeric argument to binary operator- 但这里数据中还有其他类型（fct, chr），所以这里
mutate_all()会报错。 - 这种情形，用
mutate_if()
## # A tibble: 32 × 12
## rowname mpg cyl disp hp drat wt qsec vs am gear carb
## <chr> <dbl> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <fct> <fct> <fct> <fct>
## 1 1 0.451 6 0.222 0.205 0.525 0.283 0.233 0 1 4 4
## 2 2 0.451 6 0.222 0.205 0.525 0.348 0.3 0 1 4 4
## 3 3 0.528 4 0.0920 0.145 0.502 0.206 0.489 1 1 4 1
## 4 4 0.468 6 0.466 0.205 0.147 0.435 0.588 1 0 3 1
## 5 5 0.353 8 0.721 0.435 0.180 0.493 0.3 0 0 3 2
## 6 6 0.328 6 0.384 0.187 0 0.498 0.681 1 0 3 1
## 7 7 0.166 8 0.721 0.682 0.207 0.526 0.160 0 0 3 4
## 8 8 0.596 4 0.189 0.0353 0.429 0.429 0.655 1 0 4 2
## 9 9 0.528 4 0.174 0.152 0.535 0.419 1 1 0 4 2
## 10 10 0.374 6 0.241 0.251 0.535 0.493 0.452 1 0 4 4
## # ℹ 22 more rows
funs <- list(
centered = mean, # Function object
scaled = ~ . - mean(.) / sd(.) # Purrr-style lambda
)
iris %>%
mutate_if(is.numeric, funs)## # A tibble: 150 × 13
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## <dbl> <dbl> <dbl> <dbl> <fct>
## 1 5.1 3.5 1.4 0.2 setosa
## 2 4.9 3 1.4 0.2 setosa
## 3 4.7 3.2 1.3 0.2 setosa
## 4 4.6 3.1 1.5 0.2 setosa
## 5 5 3.6 1.4 0.2 setosa
## 6 5.4 3.9 1.7 0.4 setosa
## 7 4.6 3.4 1.4 0.3 setosa
## 8 5 3.4 1.5 0.2 setosa
## 9 4.4 2.9 1.4 0.2 setosa
## 10 4.9 3.1 1.5 0.1 setosa
## # ℹ 140 more rows
## # ℹ 8 more variables: Sepal.Length_centered <dbl>, Sepal.Width_centered <dbl>,
## # Petal.Length_centered <dbl>, Petal.Width_centered <dbl>,
## # Sepal.Length_scaled <dbl>, Sepal.Width_scaled <dbl>,
## # Petal.Length_scaled <dbl>, Petal.Width_scaled <dbl>37.8 across函数
数据框中向量de方向，事实上可以看做有两个方向，横着看是row-vector，竖着看是col-vector。
- colwise:
group_by() %>% summarise/mutate + across() - rowwise:
rowwise()/nest_by() %>% summarise/mutate + c_across()
比如
iris %>%
dplyr::group_by(Species) %>%
dplyr::summarise(
across(starts_with("Sepal"), mean),
Area = mean(Petal.Length * Petal.Width),
across(starts_with("Petal"), min)
)37.8.1 across函数替代scope函数
强大的across()函数，替代以上scope函数(_if, _at, 和 _all函数), 同时slice_max(), slice_min(), slice_n() 将替代 top_n()函数。请参考阅读第?? 章。
df %>% mutate_if(is.numeric, mean, na.rm = TRUE)
# ->
df %>% mutate(across(is.numeric, mean, na.rm = TRUE))
df %>% mutate_at(vars(x, starts_with("y")), mean, na.rm = TRUE)
# ->
df %>% mutate(across(c(x, starts_with("y")), mean, na.rm = TRUE))
df %>% mutate_all(mean, na.rm = TRUE)
# ->
df %>% mutate(across(everything(), mean, na.rm = TRUE))37.8.2 更方便的colwise操作
# multiple
df <- tibble(x = 1:3, y = 3:5, z = 5:7)
mult <- list(x = 1, y = 10, z = 100)
df %>% mutate(across(all_of(names(mult)), ~ .x * mult[[cur_column()]]))
# weights
df <- tibble(x = 1:3, y = 3:5, z = 5:7)
df
weights <- list(x = 0.2, y = 0.3, z = 0.5)
df %>% dplyr::mutate(
across(all_of(names(weights)),
list(wt = ~ .x * weights[[cur_column()]]),
.names = "{col}.{fn}"
)
)
# cutoffs
df <- tibble(x = 1:3, y = 3:5, z = 5:7)
df
cutoffs <- list(x = 2, y = 3, z = 7)
df %>% dplyr::mutate(
across(all_of(names(cutoffs)), ~ if_else(.x > cutoffs[[cur_column()]], 1, 0))
)