How to concatenate character strings based on condition in r?

Question

I need to prepare queries that are made of characters strings (DOI, Digital Object Identifier) stored in a data frame. All strings associated with the same case have to be joined to produce one query.

The df looks like this:

Case	DOI
1	1212313/dfsjk23
1	322332/jdkdsa12
2	21323/xsw.w3
2	311331313/q1231
2	1212121/1231312

The output should be a data frame looking like this:

Case	Query
1	DO=(1212313/dfsjk23 OR 322332/jdkdsa12)
2	DO=(21323/xsw.w3 OR 311331313/q1231 OR 1212121/1231312)

The prefix ("DO="), suffix (")") and "OR" are not critical, I can add them later, but how to aggregate character strings based on a case number?

Onyambu · Accepted Answer · 2021-06-02 17:41:12Z

2

In base R you could do:

aggregate(DOI~Case, df1, function(x) sprintf('DO=(%s)', paste0(x, collapse = ' OR ')))
  Case                                                     DOI
1    1                 DO=(1212313/dfsjk23 OR 322332/jdkdsa12)
2    2 DO=(21323/xsw.w3 OR 311331313/q1231 OR 1212121/1231312)

if Using R 4.1.0

aggregate(DOI~Case, df1, \(x)sprintf('DO=(%s)', paste0(x, collapse = ' OR ')))

answered Jun 2, 2021 at 17:41

Onyambu

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akrun · Accepted Answer · 2021-06-02 17:37:12Z

0

We can use glue with str_c to collapse the 'DOI' column after grouping by 'Case'

library(stringr)
library(dplyr)
df1 %>%
   group_by(Case) %>%
   summarise(Query = glue::glue("DO=({str_c(DOI, collapse= ' OR ')})"))

-output

## A tibble: 2 x 2
#   Case Query                                                  
#  <int> <glue>                                                 
#1     1 DO=(1212313/dfsjk23 OR 322332/jdkdsa12)                
#2     2 DO=(21323/xsw.w3 OR 311331313/q1231 OR 1212121/1231312)

data

df1 <- structure(list(Case = c(1L, 1L, 2L, 2L, 2L), DOI = c("1212313/dfsjk23", 
"322332/jdkdsa12", "21323/xsw.w3", "311331313/q1231", "1212121/1231312"
)), class = "data.frame", row.names = c(NA, -5L))

edited Jun 2, 2021 at 17:37

answered Jun 2, 2021 at 17:25

akrun

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1 Comment

Rom Over a year ago

New to this site, thank you for pointing this out.

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