在嵌套数据框中，将信息从一个列表列传递到另一个列表中应用的函数 [英] In nested data frame, pass information from one list column to function applied in another

问题描述

我正在处理一个报告，必须将大量类似的数据框导出到Word中漂亮的表中.我的目标是使用flextable生成表并使用purrr/tidyverse将所有格式设置过程应用于嵌套数据帧中的所有行，以一次性实现这一目标.这是我的数据框的样子:

I am working on a report for which I have to export a large number of similar data frames into nice looking tables in Word. My goal is to achieve this in one go, using flextable to generate the tables and purrr / tidyverse to apply all the formatting procedures to all rows in a nested data frame. This is what my data frame looks like:

df <- data.frame(school = c("A", "B", "A", "B", "A", "B"),
            students = c(round(runif(6, 1, 10), 0)),
            grade = c(1, 1, 2, 2, 3, 3))

我想为学校"列中的所有组生成单独的表，并开始使用tidyr中的nest()函数.

I want to generate separate tables for all groups in column 'school' and started by using the nest() function within tidyr.

list <- df %>% 
        group_by(school) %>%
        nest()

这给了我一个嵌套的数据框，我可以使用purrr在flextable中应用功能:

This gives me a nested data frame to which I can apply the functions in flextable using purrr:

list <- list %>% 
        mutate(ftables = map(data, flextable)) %>%
        mutate(ftables = purrr::map(ftables, ~ set_header_labels(.,
                                               students = "No of students",
                                               grade = "Grade")))

第一个mutate为每个学校生成一个带有可伸缩对象的新列，第二个mutate根据对象中保存的列名将标题标签应用于表格.

The first mutate generates a new column with flextable objects for each school, and the second mutate applies header labels to the table, based on the column names that are saved in the object.

我现在的目标是添加另一个基于学校名称的标题.此值位于名为school的列表列中，该列与在列表列ftables中生成的表按行对应.如何使用purrr或任何其他过程将学校的名称传递给ftables中的add_header函数?

My goal is now to add another header that is based on the name of the school. This value resides in the list column entitled school, which corresponds row-wise to the tables generated in the list column ftables. How can I pass the name of the school to the add_header function within ftables, using purrr or any other procedure?

预期产量
通过此过程，我已经能够实现个别学校的目标(稍后将合并相同的标题单元格):

Expected output
I have been able to achieve what I want for individual schools with this procedure (identical header cells will later be merged):

school.name <- "A"

ftable.a <- df %>%
            filter(school == "A") %>% 
            select(-school) %>%
            flextable() %>%
            set_header_labels(students = "No of students",
                              grade = "Grade") %>%
            add_header(students = school.name,
                       grade = school.name)

ftable.a

推荐答案

程序包purrr提供您应使用的功能map2:

package purrr provides function map2 that you should use:

library(flextable)
library(magrittr)
library(dplyr)
library(tidyr)
library(purrr)


df <- data.frame(school = c("A", "B", "A", "B", "A", "B"),
                 students = c(round(runif(6, 1, 10), 0)),
                 grade = c(1, 1, 2, 2, 3, 3))
byschool <- df %>% 
  group_by(school) %>%
  nest()

byschool <- byschool %>% 
  mutate(ftables = map(data, flextable)) %>%
  mutate(ftables = purrr::map(
    ftables, ~ set_header_labels(.,
                                 students = "No of students",
                                 grade = "Grade"))) %>% 
  mutate(ftables = purrr::map2(ftables, school, function(ft, h){
    add_header(ft, students = h, grade = h)
  } )) 

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