*computation of some network variables.
*please check and adjust to your own purposes. 
*IMPORTANT: use the help function of SPSS if you have problems with understanding some comments.

*how many empty fields?.
*calculation of string length.
COMPUTE co1_stri_len = LENGTH(RTRIM(eam)) .
COMPUTE co2_stri_len = LENGTH(RTRIM(ebm)) .
COMPUTE co3_stri_len = LENGTH(RTRIM(ecm)) .
COMPUTE co4_stri_len = LENGTH(RTRIM(edm)) .
COMPUTE co5_stri_len = LENGTH(RTRIM(eem)) .
EXECUTE .

*count how often string length=0.
COUNT
  no_advice_contact = co1_stri_len co2_stri_len co3_stri_len co4_stri_len co5_stri_len (0)  .
VARIABLE LABELS no_advice_contact 'number of empty name generators' .
EXECUTE .



COMPUTE net_size_without_ego = 5 - no_advice_contact .
EXECUTE .

compute net_size=net_size_without_ego+1.

COMPUTE possible_ties = (net_size * (net_size - 1) )/ 2 .
EXECUTE .


*count number of ties in the ego network.
COUNT
  nr_ties = en1 en2 en3 en4 en5 en6 en7 en8 en9 en10 (2 3)  .
VARIABLE LABELS nr_ties 'number of ties in the network' .
EXECUTE .


IF  (possible_ties > 0) density_dich= (nr_ties + net_size_without_ego) / possible_ties.
EXECUTE.

*some respondents didn't fill in the inter-alter-response matrix correctly.
*they have to be left out.

USE ALL.
COMPUTE filter_$=(density_dich  <=  1).
VARIABLE LABEL filter_$ 'density_dich  <=  1 (FILTER)'.
VALUE LABELS filter_$ 0 'Not Selected' 1 'Selected'.
FORMAT filter_$ (f1.0).
FILTER BY filter_$.
EXECUTE.



RECODE
  net_size
  (0=1)  (1 thru Highest=0)  (ELSE=SYSMIS)  INTO  miss_total_net .
VARIABLE LABELS miss_total_net 'no name generator at all filled in'.

EXECUTE .