frequency tool

SandraMargriter

Does anyone know why the case_item field was eliminated from the frequency tool in ArcGIS Desktop? In ArcInfo Workstation the option to add a case_item made it very easy to join the frequency table to the feature table. This question was initially asked in 2007 (http://forums.esri.com/thread.asp?c=93&f=1729&t=233587), but did not get a response.

KimOllivier

I miss this function too, especially when attempting to port  AML code to  Python tools.

Here is a python script  that  I called FrequencyWithCase to add back the functionality.
It was not too hard, I can add the case ID as the records are read in a single pass updateCursor.

# FrequencyWithCase.py
# do it properly ESRI
# 19 May 2010
# add a case item to the source table
# like Workstation

import arcgisscripting,sys,os

try :
    table = sys.argv[1]
    strFields = sys.argv[2]
except :
    table = "e:/data/nzpost/paf2010/geopaf.gdb/pafpost"
    strFields = "postcode;postcode_1"

gp = arcgisscripting.create(9.3)
casefld = "case"
ws = os.path.dirname(table)
tabname = os.path.basename(table)

gp.Workspace = ws

if len(gp.Listfields(table,casefld)) == 0 :
    result = gp.AddField(table,casefld,"LONG")
    print result.GetOutput(0)
else :
    # name = gp.AddField(table,"case1","LONG")
    print casefld,"Exists"
if gp.ListFields(table,casefld) == None :
    raise Exception,"no case field"
seqfld = 'sequence'
if len(gp.Listfields(table,seqfld)) == 0 :
    result = gp.AddField(table,seqfld,"LONG")
    print result.GetOutput(0)
else :
    # name = gp.AddField(table,"case1","LONG")
    print seqfld,"Exists"
if gp.ListFields(table,seqfld) == None :
    raise Exception,"no sequence field"
# make a dictionary with a combo key
# populate the source table as we go
# export the dictionary at the end

# make a tuple of all fields
# check if its in dictionary
# if it is increment counter
# otherwise add new entry
# retrieve number
# put number into index or back on table

# 
dFreq = {}
lstFields = strFields.split(";")
print lstFields
cur = gp.UpdateCursor(table)
row = cur.next()
n = 0
ccase = 0
while row:
    combo = []
    for f in lstFields :
        combo.append( row.GetValue(f) )
    combo = tuple(combo)
    if dFreq.has_key(combo) :
        thiscase,freq = dFreq[combo]
        dFreq[combo] = (thiscase,freq+1)
        row.case = thiscase
        row.sequence = freq+1
    else :
        ccase+=1
        dFreq[combo] = (ccase,1)
        row.case = ccase
        row.sequence = 1
    cur.UpdateRow(row)
##    if n > 1000 :
##        break
    n+=1
    row = cur.next()
del cur,row
print

print "case freq"
keytab = dFreq.values()
keytab.sort()
##for x in keytab:
##    print "%4d %4d" % x
print len(dFreq),"cases"

# write out frequency table with case item

fTab = tabname+"Freq"
if gp.Exists(fTab) :
    gp.Delete(fTab)
gp.CreateTable(ws,fTab)
gp.AddField(fTab,casefld,"LONG")
gp.AddField(fTab,"Frequency","LONG")
dscTable = gp.Describe(table)
dType = {"String":"TEXT","Integer":"LONG"}
for f in lstFields:
    fType = dType[gp.ListFields(table,f)[0].type]
    gp.AddField(fTab,f,fType) # may not be a "long" in general case
    print f,"added to",fTab    
cur = gp.InsertCursor(fTab)
for k in dFreq.keys():
    ## print dFreq[0],dFreq[1],dFreq
    row = cur.NewRow()
    row.case = dFreq[0]
    row.Frequency = dFreq[1]
    n = 0
    for i in k:
        ##print i,n,lstFields
        fld = lstFields
        row.SetValue(fld, i)
        n+=1
    cur.InsertRow(row)
del cur,row
print "Done"