ddply 分组求均值 r

小鱼儿 2023-02-14 02:20 10阅读 0赞

方法一：

建立一个矩阵

dfx <- data.frame(
      group = c(rep('A', 8), rep('B', 15), rep('C', 6)),
      sex = sample(c("M", "F"), size = 29, replace = TRUE),
      age = runif(n = 29, min = 18, max = 54)
    )

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ_size_16_color_FFFFFF_t_70][]

利用plyr里的ddply可以分组求均值和sum

ddply(dfx, .(group, sex), summarize,
     mean = round(mean(age), 2),
     sd = round(sd(age), 2))

结果如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ_size_16_color_FFFFFF_t_70 1][]

方法二

使用dplyr包的group\_by和summarize功能

library(dplyr)
    dfx %>%
      as_tibble() %>% 
      dplyr::group_by(group,sex) %>%
      dplyr::summarize(
        n = n(),
        mean_age = mean(age, na.rm = T),
        median = median(age, na.rm = T)
      )

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ_size_16_color_FFFFFF_t_70 2][]

参考链接

[https://www.rdocumentation.org/packages/plyr/versions/1.8.6/topics/ddply][https_www.rdocumentation.org_packages_plyr_versions_1.8.6_topics_ddply]

[https://dplyr.tidyverse.org/reference/summarise.html][https_dplyr.tidyverse.org_reference_summarise.html]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200531053318419.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200531055428949.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1MTkwOQ==,size_16,color_FFFFFF,t_70
[https_www.rdocumentation.org_packages_plyr_versions_1.8.6_topics_ddply]: https://www.rdocumentation.org/packages/plyr/versions/1.8.6/topics/ddply
[https_dplyr.tidyverse.org_reference_summarise.html]: https://dplyr.tidyverse.org/reference/summarise.html