I have a dt similar to below, with chr data held in the Description column like below. I need to count the number of times certain strings of characters occur in that column, and sum them in the Occurrences column.
In the table below, it would be counting the number of times "A18" or "A19" appears.
| ID | Date | Description | Occurrences |
|---|---|---|---|
| 1 | 2020-01-01 | A1901,A1804,A2008,AB06 | 2 |
| 2 | 2020-01-14 | A1402,A1805,A1902 | 2 |
| 3 | 2018-02-25 | A1702 | 0 |
I'm very new to R and datatables, so haven't tried much. I've searched, but only found how to count occurrences of whole strings, not within them.
CodePudding user response：
Use str_count:
library(stringr)
library(dplyr)
df %>%
mutate(Occurences2 = str_count(Description, "A18|A19"))