Frequency Count of Zotero Tags via Stata

* tag_count.do
*   Creates dataset of tags with frequencies from exported Zotero database
*   Assumes Zotero library has been exported to "Library.csv" in current directory
*   Benjamin L. Read, http://benread.net

*** Import the library
import delimited using Library.csv, varnames(1) case(lower) clear
tostring manualtags, replace       // should already be strings but may not be e.g. if all null
tostring automatictags, replace
replace manualtags="" if manualtags=="."
replace automatictags="" if automatictags=="."

* One efficient approach would be to concatenate the "manualtags" and "automatictags" at the outset
*   Instead, we process the two types of tags separately in case that proves useful

*** Count each item's tags
* Manual tags
egen n_man_sc = noccur(manualtags), string(";") // Counts semicolon delimiters in tags string
gen int n_man_tags = n_man_sc + 1
replace n_man_tags = 0 if manualtags == ""
quietly summarize n_man_tags
local max_man_tags = r(max) // The maximum # of tags in any item
drop n_man_sc
* Automatic tags
egen n_auto_sc = noccur(automatictags), string(";") // Counts semicolon delimiters in tags string
gen int n_auto_tags = n_auto_sc + 1
replace n_auto_tags = 0 if automatictags == ""
quietly summarize n_auto_tags
local max_auto_tags = r(max) // The maximum # of tags in any item
drop n_auto_sc

*** Process manual tags
if `max_man_tags' > 0 {
  * Generate new string variables for the individual tags
  forvalues t = 1/`max_man_tags' {
    quietly gen str man_tag`t' = ""
  }
  * Loop through all observations and parse out the individual tags from the original string
  forvalues item = 1/`=_N' {              // Loop over all items
    local tokentarget = manualtags[`item']
    tokenize "`tokentarget'", parse(";") // double quotes needed around target, else commas produce error
    local ntokens = (n_man_tags[`item'] * 2) - 1 // delimiters are tokens too
    forvalues token = 1(2)`ntokens' {              // Loop over all tokens for this item
      local tag = (`token'+1)/2
      quietly replace man_tag`tag' = "``token''" in `item'  // Extract one tag
    }  // End token loop
  } // End item loop
  * Create new dataset in which each observation has one tag from one item
  preserve
  keep man_tag*
  rename man_tag* tag*
  gen newid=_n
  reshape long tag, i(newid) j(tagnum)
  drop if tag == ""
  save manual_tags, replace
  restore
}

*** Process automatic tags
if `max_auto_tags' > 0 {
  * Generate new string variables for the individual tags
  forvalues t = 1/`max_auto_tags' {
    quietly gen str auto_tag`t' = ""
  }
  * Loop through all observations and parse out the individual tags from the original string
  forvalues item = 1/`=_N' {              // Loop over all items
    local tokentarget = automatictags[`item']
    tokenize "`tokentarget'", parse(";") // double quotes needed around target, else commas produce error
    local ntokens = (n_auto_tags[`item'] * 2) - 1 // delimiters are tokens too
    forvalues token = 1(2)`ntokens' {              // Loop over all tokens for this item
      local tag = (`token'+1)/2
      quietly replace auto_tag`tag' = "``token''" in `item'  // Extract one tag
    }  // End token loop
  } // End item loop
  * Create new dataset in which each observation has one tag from one item
  keep auto_tag*
  rename auto_tag* tag*
  gen newid=_n
  reshape long tag, i(newid) j(tagnum)
  drop if tag == ""
  save automatic_tags, replace
}

*** Select manual tags, automatic tags, or both (as written, assumes both)
clear
cap use manual_tags             // assumes you want to include manual tags; comment this out otherwise
cap append using automatic_tags // assumes you want to include automatic tags; comment this out otherwise
cap erase manual_tags.dta       // clean up
cap erase automatic_tags.dta    // clean up

*** Collapse the dataset to create a per-tag count
gen freq=1
di as text _newline "Total number of tags: " as result _N
collapse (count) freq, by(tag) // creates new dataset; unit is a discrete tag
di as text _newline "Total number of unique tags: " as result _N
gsort - freq + tag // sorts in descending order of frequency. Comment this out to keep the tags in alphabetical order
di as text _newline "Top ten most frequent tags:"
list in 1/10 // type "list" without arguments for a full list, naturally