按项目填充时间序列中缺失的日期月份

Question

I am fairly new to R and I am trying to do the following task:

I have the following dataset:

df1 <- data.frame(ITEM = c("A","A","A","A","A","B","B","B","B","B"),
              Date = c("Jan-2020","Feb-2020","May-2020","Jun-2020","Jul-2020","Jan-2020","Apr-2020","Jun-2020","Jul-2020","Aug-2020"))

Here is an image:

I have used the library "zoo" to change the date column into yearmon and I am trying to create rows for the missing "yearmon" dates. So something like this:

Anyone has any idea how I can do this?

Thank you

Answer 1

You can create a sequence of yearmon objects for each ITEM and use it in complete .

library(dplyr)
library(zoo)
library(tidyr)

df1 %>%
  mutate(Date = as.yearmon(Date, '%b-%Y')) %>%
  group_by(ITEM) %>%
  complete(Date = seq(min(Date), max(Date), 1/12)) %>%
  ungroup

#   ITEM  Date     
#   <chr> <yearmon>
# 1 A     Jan 2020 
# 2 A     Feb 2020 
# 3 A     Mar 2020 
# 4 A     Apr 2020 
# 5 A     May 2020 
# 6 A     Jun 2020 
# 7 A     Jul 2020 
# 8 B     Jan 2020 
# 9 B     Feb 2020 
#10 B     Mar 2020 
#11 B     Apr 2020 
#12 B     May 2020 
#13 B     Jun 2020 
#14 B     Jul 2020 
#15 B     Aug 2020 

If you want a sequence of date objects you can use:

df1 %>%
  mutate(Date = as.Date(as.yearmon(Date, '%b-%Y'))) %>%
  group_by(ITEM) %>%
  complete(Date = seq(min(Date), max(Date), 'month')) %>%
  ungroup()