如何按 R 上的日期与两年之间的时间合并？

Question

所以我有了第一个数据集

Company	Director	Dir_Date
AB	Alexander	2014
AB	Justin	2020

然后我们了解到，在 2014 年至 2019 年期间，AB 的董事是 Alexander。

我的第二个数据集是这样的

Company	Results	Date
AB	Good	2014
AB	Good	2015
AB	Bad	2016

每年等等。我想通过按公司和日期合并来获得这个输出：

Company	Results	Date	Director
AB	Good	2014	Alexander
AB	Good	2015	Alexander
AB	Bad	2016	Alexander

Answer 1

在扩展示例中，展示如何硬编码其他可能的年份值

df_m <- read.table(text = 'Company  Director    Dir_Date
AB  Alexander   2014
AB  Justin  2020', header = T)

df <- read.table(text = ' Company   Results Date
AB  Good    2014
AB  Good    2015
AB  Bad 2016
AB Something  2021', header = T)

library(tidyverse)
df %>% left_join(df_m %>% group_by(Company) %>% complete(Dir_Date = 2000:2021) %>%
                   fill(Director, .direction = 'down'),
                 by = c('Company' = 'Company', 'Date' = 'Dir_Date'))


  Company   Results Date  Director
1      AB      Good 2014 Alexander
2      AB      Good 2015 Alexander
3      AB       Bad 2016 Alexander
4      AB Something 2021    Justin

---

或

df_m <- read.table(text = 'Company  Director    Dir_Date
AB  Alexander   2014
AB  Justin  2020', header = T)

df <- read.table(text = ' Company   Results Date
AB  Good    2012
AB  Good    2015
AB  Bad 2016
AB Something  2021', header = T)

library(tidyverse)
df %>% left_join(df_m %>% group_by(Company) %>% complete(Dir_Date = 2000:2021) %>%
                   fill(Director, .direction = 'down'),
                 by = c('Company' = 'Company', 'Date' = 'Dir_Date'))
#>   Company   Results Date  Director
#> 1      AB      Good 2012      <NA>
#> 2      AB      Good 2015 Alexander
#> 3      AB       Bad 2016 Alexander
#> 4      AB Something 2021    Justin

^{由reprex package (v2.0.0) 于 2021-05-20 创建}

---

df_m <- read.table(text = 'Company  Director    Dir_Date
AB  Alexander   2014
AB  Justin  2020', header = T)

df <- read.table(text = ' Company   Results Date
AB  Good    2014
AB  Good    2015
AB  Bad 2016', header = T)

library(tidyverse)
df %>% left_join(df_m %>% group_by(Company) %>% complete(Dir_Date = seq(min(Dir_Date), max(Dir_Date), 1)) %>%
                   fill(Director, .direction = 'down'),
                 by = c('Company' = 'Company', 'Date' = 'Dir_Date'))
#>   Company Results Date  Director
#> 1      AB    Good 2014 Alexander
#> 2      AB    Good 2015 Alexander
#> 3      AB     Bad 2016 Alexander

^{由reprex package (v2.0.0) 于 2021-05-20 创建}