Date:         Mon, 26 Jan 2009 10:39:37 -0800
Reply-To:     Albert-jan Roskam <fomcl@yahoo.com>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Albert-jan Roskam <fomcl@yahoo.com>
Subject:      Re: delete string variables
Comments: To: Cristiano <rivoli2@gmail.com>
Content-Type: text/plain; charset=us-ascii

Hi!

The code below works, but it's not very concise. Maybe Jon Peck or somebody else has an ingenious two-line solution ;-)
v1, v4, blankstr and fubar are the vars to be deleted.

Cheers!!
Albert-Jan

* create a sample dataset: .
data list free / v1 to v4.
begin data
0 0 1 0
0 1 0 0
0 0 0 0
0 1 0 0
0 0 0 0
0 1 1 0
0 0 0 0
0 0 0 0
0 0 1 0
0 0 0 0
end data.
recode all (0 = sysmis).
string blankstr fubar (a8).
compute blankstr = " " .
compute fubar = " " .
exe.

* actual code.
begin program.
import spss, spssaux

spss.Submit("""
compute const = 1.
exe.
dataset name source.""")

# check numeric vars
numDict = spssaux.VariableDict(variableType='numeric')
cmd = ["aggr out = * / break = const / "] + ["  " + var.VariableName + " = sum (" + var.VariableName + ") / " \
 for var in numDict if var.VariableName != "const"] + ["."]
spss.Submit(cmd)
spss.Submit("""
dataset name thisone.
dataset activate source.""")

# check string vars
strDict = spssaux.VariableDict(variableType='string')
for var in strDict:
        spss.Submit("compute len_%s = length(rtrim(ltrim( %s )))." % (var.VariableName, var.VariableName))
cmd = ["aggr out = * / break = const / "] + ["   " + var.VariableName + " = sum (len_" + var.VariableName + ") / " \
 for var in strDict if var.VariableName != "const"] + ["."]
spss.Submit(cmd)

# build list of vars to be deleted
spss.Submit("""
dataset name thatone window = asis.
match files / file = thisone / file = thatone / by = const.
recode all (sysmis = 0) (else = copy).
exe.""")
dataCursor=spss.Cursor()
oneRow=dataCursor.fetchone()
varDict = spssaux.VariableDict()
delvars = [str(var) for k, var in enumerate(varDict) if oneRow[k] == 0]
dataCursor.close()
spss.Submit("dataset activate source.")
lastvar = ' '.join(spssaux.GetVariableNamesList()[-1:])
spss.Submit("""
add files / file = * / drop = %s const to %s.
exe.
dataset close all.
""" % (' '.join(delvars), lastvar))
end program.

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