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      name:  <unnamed>
       log:  C:\Projects\Analysis\Calendar tutorial\Stata\Example1.log
  log type:  text
 opened on:  31 Aug 2017, 00:30:08

. * DHS Calendar Tutorial - Example 1
. * Basic string manipulation
. 
. * download the model dataset for individual women's recode: "ZZIR62FL.DTA" 
. * the model datasets are available at http://dhsprogram.com/data/download-model-datasets.cfm
. 
. * change to a working directory where the data are stored
. * or add the full path to the 'use' command below
. cd "C:\Data\DHS_model"
C:\Data\DHS_model

. 
. * open the dataset, selecting just the variables we are going to use
. use vcal_1 v000 v005 v007 v008 v017 v018 v019 using "ZZIR62FL.DTA", clear

. 
. 
. * 1) display column 1 of the calendar for the first 6 respondents
. list vcal_1 in 1/5

     +----------------------------------------------------------------------------------+
     |                                                                           vcal_1 |
     |----------------------------------------------------------------------------------|
  1. |               00000BPPPPPPPP00000000000000000000000BPPPPPPPP00000000000000000000 |
  2. |               PPPPPP000000000000000000000000BPPPPPPPP000000000000000000000000000 |
  3. |               000000000000000000000000000000000000000000000000000000000000000000 |
  4. |               0000000000BPPPPPPPP00000000000BPPPPPPPP000000000000000000000000000 |
  5. |               0BPPPPPPPP000000000000000000000000BPPPPPPPP00000000000000000000000 |
     +----------------------------------------------------------------------------------+

. 
. 
. * 2) calculate the full length of calendar by displaying length of strings
. gen vcal_len = strlen(vcal_1)

. label variable vcal_len "length of calendar"

. list vcal_len in 1/5

     +----------+
     | vcal_len |
     |----------|
  1. |       80 |
  2. |       80 |
  3. |       80 |
  4. |       80 |
  5. |       80 |
     +----------+

. 
. 
. * 3) take a piece of a string from column 1
. gen piece = substr(vcal_1,44,12) // start at position 44 for 12 characters

. label variable piece "piece of calendar"

. list piece in 1/5

     +--------------+
     |        piece |
     |--------------|
  1. | 00000000BPPP |
  2. | 0BPPPPPPPP00 |
  3. | 000000000000 |
  4. | 0BPPPPPPPP00 |
  5. | 00000BPPPPPP |
     +--------------+

. 
. 
. * 4) find the position of a substring within a string
. gen pos = strpos(vcal_1,"P") // look for first occurrence of "P"

. label variable pos "position in calendar"

. list pos in 1/5

     +-----+
     | pos |
     |-----|
  1. |  21 |
  2. |  15 |
  3. |   0 |
  4. |  26 |
  5. |  17 |
     +-----+

. 
. 
. * 5) reverse a string
. gen rev_cal = reverse(vcal_1) // calendar from oldest to most recent month (L to R)

. label variable rev_cal "reversed calendar"

. list rev_cal in 1/5

     +----------------------------------------------------------------------------------+
     |                                                                          rev_cal |
     |----------------------------------------------------------------------------------|
  1. | 00000000000000000000PPPPPPPPB00000000000000000000000PPPPPPPPB00000               |
  2. | 000000000000000000000000000PPPPPPPPB000000000000000000000000PPPPPP               |
  3. | 000000000000000000000000000000000000000000000000000000000000000000               |
  4. | 000000000000000000000000000PPPPPPPPB00000000000PPPPPPPPB0000000000               |
  5. | 00000000000000000000000PPPPPPPPB000000000000000000000000PPPPPPPPB0               |
     +----------------------------------------------------------------------------------+

. 
. 
. * 6) trim a string of leading and trailing spaces
. gen trim_cal = trim(vcal_1)

. label variable trim_cal "trimmed calendar"

. list trim_cal in 1/5

     +--------------------------------------------------------------------+
     |                                                           trim_cal |
     |--------------------------------------------------------------------|
  1. | 00000BPPPPPPPP00000000000000000000000BPPPPPPPP00000000000000000000 |
  2. | PPPPPP000000000000000000000000BPPPPPPPP000000000000000000000000000 |
  3. | 000000000000000000000000000000000000000000000000000000000000000000 |
  4. | 0000000000BPPPPPPPP00000000000BPPPPPPPP000000000000000000000000000 |
  5. | 0BPPPPPPPP000000000000000000000000BPPPPPPPP00000000000000000000000 |
     +--------------------------------------------------------------------+

. 
. 
. * 7) display the length of calendar actually used, from the trimmed version
. gen vcal_used = strlen(trim_cal)

. label variable vcal_used "length of calendar used"

. * should be the same as v019
. list vcal_used v019 in 1/5

     +-----------------+
     | vcal_u~d   v019 |
     |-----------------|
  1. |       66     66 |
  2. |       66     66 |
  3. |       66     66 |
  4. |       66     66 |
  5. |       66     66 |
     +-----------------+

. 
end of do-file
      name:  <unnamed>
       log:  C:\Projects\Analysis\Calendar tutorial\Stata\Example1.log
  log type:  text
 closed on:  31 Aug 2017, 00:30:08
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