How can I create a loop where i only take words that start with capital letters

Question

I have an excel sheet with a lot of rows and i want: to split the rows in a specific column by commas (this column describes ancestry and it has numbers and commas), then create a function where i only take words that start with capital letters. Then abstract these words and put them in a loop, so I can create a list of words that go together in a row that start with capital letters. After that i want to create a list where i can see the frequencies of each of these words.

I used the function str_extract_all(data$INITIAL SAMPLE DESCRIPTION, "\b[A-Z]\w*") |> unique() Where INITIAL SAMPLE DESCRIPTION is the name of the column of my interest.

Answer 1

Something like this? Extract words with an initial capital letter followed by any alphabetic character zero or more times.
To table the result above, well, unlist and table it.

x <- 'I have an excel sheet with a lot of rows and i want: to split the rows in a specific column by commas (this column describes ancestry and it has numbers and commas), then create a function where i only take words that start with capital letters. Then abstract these words and put them in a loop, so I can create a list of words that go together in a row that start with capital letters. After that i want to create a list where i can see the frequencies of each of these words.
I used the function str_extract_all(data$INITIAL SAMPLE DESCRIPTION, "\\b[A-Z]\\w*") |> unique() Where INITIAL SAMPLE DESCRIPTION is the name of the column of my interest.
'
cap <- stringr::str_extract_all(x, "[A-Z][[:alpha:]]*")
cap
#> [[1]]
#>  [1] "I"           "Then"        "I"           "After"       "I"          
#>  [6] "INITIAL"     "SAMPLE"      "DESCRIPTION" "A"           "Z"          
#> [11] "Where"       "INITIAL"     "SAMPLE"      "DESCRIPTION"

cap |> unlist() |> table()
#> 
#>           A       After DESCRIPTION           I     INITIAL      SAMPLE 
#>           1           1           2           3           2           2 
#>        Then       Where           Z 
#>           1           1           1

^{Created on 2023-12-22 with reprex v2.0.2}

---

Apply the code above to each column element.
Written as a function:

extract_cap_words <- function(x) {
  stringr::str_extract_all(x, "[A-Z][[:alpha:]]*")
}

lapply(data$`INITIAL SAMPLE DESCRIPTION`, extract_cap_words)