针对tibble中的数值型数据，如何自定义保留小数位数？

[slsongge]

问题

下图中红框内的数值如何自定义保留小数点位数？

数据

df_01_2.zip

代码

library(plyr)
library(tidyverse)

df_01_2 <- read_csv("df_01_2.csv")

df_01_2 %>% 
  filter(!g4reading %in% NA) %>%
  group_by(kinder) %>%
  summarise_at(
    vars(g4reading), 
    list(~min(.), ~quantile(., 0.25), ~median(.), ~mean(.), ~quantile(., 0.75), ~max(.))
  )

我当前的解决方法

df_01_2 %>% 
  filter(!g4reading %in% NA) %>%
  group_by(kinder) %>%
  summarise_at(
    vars(g4reading), 
    list(~min(.), ~quantile(., 0.25), ~median(.), ~mean(.), ~quantile(., 0.75), ~max(.))
  ) %>%
  data.frame() %>%
  mutate_if(is.numeric, ~round(., 2)) %>%
  dplyr::rename(qu_1st = quantile..2, qu_3rd = quantile..5)

我的解决方法返回的结果如下图，其中红框的内容不知道为啥保留了一位小数？

[JiaxiangBU]

@slsongge

$ unzip data/df_01_2.zip
Archive:  data/df_01_2.zip
  inflating: df_01_2.csv

下图中红框内的数值如何自定义保留小数点位数？

library(tidyverse)

df_01_2 <- read_csv(here::here("jinxiaosong/data/df_01_2.csv"))

## Parsed with column specification:
## cols(
##   race = col_character(),
##   classtype = col_double(),
##   yearssmall = col_double(),
##   hsgrad = col_double(),
##   g4math = col_double(),
##   g4reading = col_double(),
##   kinder = col_character()
## )

df_01_2 %>% head() %>% 
    knitr::kable("markdown")

race	classtype	yearssmall	hsgrad	g4math	g4reading	kinder
white	3	0	NA	NA	NA	regular with aid
black	3	0	NA	706	661	regular with aid
white	3	0	1	711	750	regular with aid
black	1	4	NA	672	659	small
white	2	0	NA	NA	NA	regular
white	3	0	NA	NA	NA	regular with aid

df_01_2 %>% filter(is.na(g4reading)) %>% head() %>% 
    knitr::kable("markdown")

race	classtype	yearssmall	hsgrad	g4math	g4reading	kinder
white	3	0	NA	NA	NA	regular with aid
white	2	0	NA	NA	NA	regular
white	3	0	NA	NA	NA	regular with aid
white	3	0	NA	NA	NA	regular with aid
white	3	0	NA	NA	NA	regular with aid
white	3	0	NA	NA	NA	regular with aid

df <-
    df_01_2 %>%
    filter(!is.na(g4reading)) %>%
    group_by(kinder) %>%
    summarise_at(vars(g4reading),
                 list(
                     ~ min(.),
                     ~ quantile(., 0.25),
                     ~ median(.),
                     ~ mean(.),
                     ~ quantile(., 0.75),
                     ~ max(.)
                 ))

df %>% head()

## # A tibble: 3 x 7
##   kinder             min quantile..2 median  mean quantile..5   max
##   <chr>            <dbl>       <dbl>  <dbl> <dbl>       <dbl> <dbl>
## 1 regular            528        693     723  720.        749.   836
## 2 regular with aid   528        698.    722  721.        750    836
## 3 small              528        697     724  723.        750    836

有两种方法。

df %>% 
    mutate_if(is.numeric, scales::number, accuracy=1) %>% 
    knitr::kable("markdown")

kinder	min	quantile..2	median	mean	quantile..5	max
regular	528	693	723	720	749	836
regular with aid	528	698	722	721	750	836
small	528	697	724	723	750	836

# 精确到个位
df %>% 
    mutate_if(is.numeric, scales::number, accuracy=.1) %>% 
    knitr::kable("markdown")

kinder	min	quantile..2	median	mean	quantile..5	max
regular	528.0	693.0	723.0	719.9	749.2	836.0
regular with aid	528.0	697.5	722.0	720.7	750.0	836.0
small	528.0	697.0	724.0	723.4	750.0	836.0

# 精确到小数点一位
df %>% 
    mutate_if(is.numeric, scales::number, accuracy=.01) %>% 
    knitr::kable("markdown")

kinder	min	quantile..2	median	mean	quantile..5	max
regular	528.00	693.00	723.00	719.89	749.25	836.00
regular with aid	528.00	697.50	722.00	720.72	750.00	836.00
small	528.00	697.00	724.00	723.39	750.00	836.00

# 精确到小数点二位
df %>% 
    mutate_if(is.numeric, scales::number, accuracy=10) %>% 
    knitr::kable("markdown")

kinder	min	quantile..2	median	mean	quantile..5	max
regular	530	690	720	720	750	840
regular with aid	530	700	720	720	750	840
small	530	700	720	720	750	840

# 精确到十位

这个包开发的时候是为了给 ggplot2 搞单位的。

下面这个是任坤大神的。

df %>% 
    mutate_if(is.numeric, formattable::digits, digits=2) %>% 
    knitr::kable("markdown")

kinder	min	quantile..2	median	mean	quantile..5	max
regular	528.00	693.00	723.00	719.89	749.25	836.00
regular with aid	528.00	697.50	722.00	720.72	750.00	836.00
small	528.00	697.00	724.00	723.39	750.00	836.00

# 小数点后两位

最后是 base 的方法。

for (i in 1:10) {
    print(pi, digits = i)        
}
## [1] 3
## [1] 3.1
## [1] 3.14
## [1] 3.142
## [1] 3.1416
## [1] 3.14159
## [1] 3.141593
## [1] 3.1415927
## [1] 3.14159265
## [1] 3.141592654

[JiaxiangBU]

这个和

最后是 base 的方法。

for (i in 1:10) {
    print(pi, digits = i)        
}
## [1] 3
## [1] 3.1
## [1] 3.14
## [1] 3.142
## [1] 3.1416
## [1] 3.14159
## [1] 3.141593
## [1] 3.1415927
## [1] 3.14159265
## [1] 3.141592654

类似，只不过是在options(digits=n)设置。 参考 http://brucezhaor.github.io/blog/2016/05/05/read-data-1/ @slsongge