count the names in a variable

[Mike Kraft]

Hi

I have a variable that includes names with commas and I want to create a variable to represent the count of these names. Here is a dataex below

* Example generated by -dataex-. To install: ssc install dataex
clear
input str36 names
"Tom"                       
""                                                     
""                             
"John"                 
"Fisher, Eddie, Tom"
""                             
""                                                       
""                             
"Lacker"                       
end

------------------ copy up to and including the previous line ------------------

[Nick Cox]

You need two rules, it seems:

the number of commas plus 1

-- so long as the variable is not missing (empty)

See https://www.stata-journal.com/articl...article=dm0056.

[Mike Kraft]

Thanks Nick

I tried the following code. It still needs to be modified to get the correct counts but I could not fix that.

gen comma = length(trim(names))-length(trim(subinstr(names,",","",.)))

* Example generated by -dataex-. To install: ssc install dataex
clear
input str36 names double comma
"Tom"                        0
""                              0
""                              0
""                              0
""                              0
"John"                  0
"Fisher, Eddie, Tom" 2
""                              0
""                              0
""                              0
""                              0
""                              0
"Lacker"                        0
end

[Nick Cox]

NB in #2

plus 1


so long as the variable is not missing (empty)

[Mike Kraft]

Thanks, but I tried that and it does not work because of the missing obs. so I am not sure how to condition for not missing within this command:

gen comma = length(trim(names))-length(trim(subinstr(names,",","",.)))+1

[Nick Cox]

Presumably you know about if qualifiers.

With your code you could just follow up with

replace comma = 0 if trim(names) == ""

Or you could get there directly with one line:

  
 * Example generated by -dataex-. To install: ssc install dataex clear input str36 names double comma "Tom"                        0 ""                              0 ""                              0 ""                              0 ""                              0 "John"                  0 "Fisher, Eddie, Tom" 2 ""                              0 ""                              0 ""                              0 ""                              0 ""                              0 "Lacker"                        0 end 


. gen wanted = cond(trim(names) == "", 0, 1 + (strlen(names) - strlen(subinstr(names, ",", "", .))))

. sort wanted 

. list, sepby(wanted)

     +-------------------------------------+
     |              names   comma   wanted |
     |-------------------------------------|
  1. |                          0        0 |
  2. |                          0        0 |
  3. |                          0        0 |
  4. |                          0        0 |
  5. |                          0        0 |
  6. |                          0        0 |
  7. |                          0        0 |
  8. |                          0        0 |
  9. |                          0        0 |
     |-------------------------------------|
 10. |                Tom       0        1 |
 11. |               John       0        1 |
 12. |             Lacker       0        1 |
     |-------------------------------------|
 13. | Fisher, Eddie, Tom       2        3 |
     +-------------------------------------+