st: Re: keep if variable is string

["Joseph Coveney" <jcoveney@bigplanet.com>]

Shubhabrata Mukherjee wrote:

 I am using --insheet-- to read in a big file where some variables are numeric
and some are string.

 How can I keep the variables that are string only?

--------------------------------------------------------------------------------

After loading in the spreadsheet, you can drop the numeric variables with
something like the loop in the following:

sysuse auto, clear
foreach var of varlist _all {
	local variable_type : type `var'
	if strpos("`variable_type'", "str") == 1 continue
	display in smcl as text "`var' is numeric--dropping `var'"
	drop `var'
}
exit

A caution:  for some reason, -insheet- does not respect quoted numerical values,
such as "01".  It reads them in as numeric, stripping any leading zeros.  

Joseph Coveney

. clear *

. set more off

. set obs 3
obs was 0, now 3

. generate str a = string(_n, "%02.0f")

. generate str b = "B"

. list, noobs

  +--------+
  |  a   b |
  |--------|
  | 01   B |
  | 02   B |
  | 03   B |
  +--------+

. describe

Contains data
  obs:             3                          
 vars:             2                          
 size:            21 (99.9% of memory free)
----------------------------------------------------------------------
              storage  display     value
variable name   type   format      label      variable label
----------------------------------------------------------------------
a               str2   %9s                    
b               str1   %9s                    
----------------------------------------------------------------------
Sorted by:  
     Note:  dataset has changed since last saved

. tempfile tmpfil0

. quietly outsheet using `tmpfil0', names quote

. type "`tmpfil0'"
a       b
"01"    "B"
"02"    "B"
"03"    "B"

. insheet using `tmpfil0', clear
(2 vars, 3 obs)

. list, noobs

  +-------+
  | a   b |
  |-------|
  | 1   B |
  | 2   B |
  | 3   B |
  +-------+

. describe

Contains data
  obs:             3                          
 vars:             2                          
 size:            18 (99.9% of memory free)
----------------------------------------------------------------------
              storage  display     value
variable name   type   format      label      variable label
----------------------------------------------------------------------
a               byte   %8.0g                  
b               str1   %9s                    
----------------------------------------------------------------------
Sorted by:  
     Note:  dataset has changed since last saved

. exit

end of do-file




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