Find duplicates in a list/array and count them ...

Paul.Scipione at Paul.Scipione at
Fri Mar 27 20:08:27 CET 2009


I'm a newbie to Python.  I wrote a Python script which connect to my Geodatabase (ESRI ArcGIS File Geodatabase), retrieves the records, then proceeds to evaluate which ones are duplicated.  I do this using lists.  Someone suggested I use arrays instead.  Below is the content of my script.  Anyone have any ideas on how an array can improve performance?  Right now the script takes 2.5 minutes to run on a recordset of 79k+ records:

from __future__ import division
import sys, string, os, arcgisscripting, time
from time import localtime, strftime

def writeMessage(myMsg):
    print myMsg
    global log
    log = open(logFile, 'a')
    log.write(myMsg + "\n")

logFile = "c:\\temp\\" + str(strftime("%Y%m%d %H%M%S", localtime())) + ".log"

writeMessage(' ')
writeMessage(str(strftime("%H:%M:%S", localtime())) + ' begin unique values test')

# Create the Geoprocessor object
gp = arcgisscripting.create(9.3)
oid_list = []
dup_list = []
tmp_list = []
myWrkspc = "c:\\temp\\TVM Geodatabase GDIschema v6.0.2 PilotData.gdb"
myFtrCls = "\\Landbase\\T_GroundContour"

writeMessage(' ')
writeMessage('gdb: ' + myWrkspc)
writeMessage('ftr: ' + myFtrCls)
writeMessage(' ')
writeMessage(str(strftime("%H:%M:%S", localtime())) + ' retrieving recordset...')

rows = gp.SearchCursor(myWrkspc + myFtrCls,"","","GDI_OID")
row = rows.Next()
writeMessage(' ')
writeMessage(str(strftime("%H:%M:%S", localtime())) + ' processing recordset...')
while row:
    if row.GDI_OID in oid_list:
    row = rows.Next()

writeMessage(' ')
writeMessage(str(strftime("%H:%M:%S", localtime())) + ' generating statistics...')

dup_count = len(tmp_list)
tmp_list = list(set(tmp_list))

for oid in tmp_list:
    a = str(oid) + '     '
    while len(a) < 20:
        a = a + ' '
    dup_list.append(a + '(' + str(oid_list.count(oid)) + ')')

for dup in dup_list:

writeMessage(' ')
writeMessage('records    : ' + str(len(oid_list)))
writeMessage('duplicates : ' + str(dup_count))
writeMessage('% errors   : ' + str(round(dup_count / len(oid_list), 4)))
writeMessage(' ')
writeMessage(str(strftime("%H:%M:%S", localtime())) + ' unique values test complete')

del dup, dup_count, dup_list, gp, log, logFile, myFtrCls, myWrkspc
del oid, oid_list, row, rows, tmp_list


Paul J. Scipione
GIS Database Administrator
work: 602-371-7091
cell: 480-980-4721

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