topic Re: Arcpy - delete attribute data if string starts with.. in Python Questions

Arcpy - delete attribute data if string starts with..

AliciaSoto — Mon, 18 Aug 2014 21:12:56 GMT

Here's what I'm trying to do.

I have a shapefile called 'Roster' with an attribute table like the one below.

NAME	Age	Room
***John	23	B
***Alice	56	C
Tina	34	A

I would like to search the shapefile and delete any data under the field 'NAME' where the string starts with '***'

The resulting table would look like this

NAME	Age	Room
	23	B
	56	C
Tina	34	A

I figured out how to replace the '***' string with another string, but I can't figure out how to delete the entire cell....

def removeName(shapefilePath):
  cursor = arcpy.da.UpdateCursor(shapefilePath, ["NAME"]) 
  for row in cursor: 
       row[0] = row[0].replace("***", None)
       cursor.updateRow(row)
  del row
  del cursor

Re: Arcpy - delete attribute data if string starts with..

CharlieFrye — Mon, 18 Aug 2014 21:36:42 GMT

Replace the contents of the for block with:

nameStr = row[0]

if nameStr[0:3] == "***" then:

newName = nameStr.replace("***", None)

row[0] = newName

cursor.update(row)

Re: Arcpy - delete attribute data if string starts with..

CharlieFrye — Mon, 18 Aug 2014 21:38:47 GMT

nameStr = row[0]

if nameStr[0:3] == "***" then:

# This is if you wanted to just strip the ***

newName = nameStr.replace("***", None)

row[0] = newName

# set the string to nothing

row[0] = ""

cursor.update(row)

Re: Arcpy - delete attribute data if string starts with..

IanMurray — Mon, 18 Aug 2014 21:43:17 GMT

No need for the then Charlie

Re: Arcpy - delete attribute data if string starts with..

IanMurray — Mon, 18 Aug 2014 21:47:57 GMT

def removeName(shapefilePath):  
  cursor = arcpy.da.UpdateCursor(shapefilePath, ["NAME"])  
    for row in cursor:  
      nameStr = row[0]

if nameStr[0:3] == "***" :

row[0] = ""

cursor.update(row)

Re: Arcpy - delete attribute data if string starts with..

AliciaSoto — Mon, 18 Aug 2014 22:07:41 GMT

Thank you both for your help.

The code worked once I changed cursor.update(row) to cursor.updateRow(row)

Here is the final code

def removeName(shapefilePath):
  cursor = arcpy.da.UpdateCursor(shapefilePath, ["NAME"])
  for row in cursor:
    nameStr = row[0]
    if nameStr[0:3] == "***":
      row[0] = ""
    cursor.updateRow(row)
  del row
  del cursor

Re: Arcpy - delete attribute data if string starts with..

CharlieFrye — Mon, 18 Aug 2014 22:27:12 GMT

Thanks Ian--I've been writing VBA lately...

Re: Arcpy - delete attribute data if string starts with..

IanMurray — Tue, 19 Aug 2014 14:02:12 GMT

I figured it was something like that Charlie, no worries

Re: Arcpy - delete attribute data if string starts with..

RhettZufelt — Tue, 19 Aug 2014 18:04:43 GMT

Another way to see if the name starts with ***

def removeName(shapefilePath):
  cursor = arcpy.da.UpdateCursor(shapefilePath, ["NAME"])
  for row in cursor:
    nameStr = row[0]
   if nameStr.startswith("***"): 
      row[0] = ""
    cursor.updateRow(row)
  del row
  del cursor

Re: Arcpy - delete attribute data if string starts with..

JoshuaBixby — Tue, 19 Aug 2014 18:13:58 GMT

Charlie Frye wrote:

Thanks Ian--I've been writing VBA lately...

An Esri staffer writing VBA? Isn't that sacrilegious these days seeing that Esri deprecated VBA in 10.1 and has been trying unsuccessfully to retire it since then.

Re: Arcpy - delete attribute data if string starts with..

JoshuaBixby — Tue, 19 Aug 2014 19:39:11 GMT

Although I am thinking the UpdateCursor (arcpy.da) might still be faster, one could also use Make Feature Layer or Select Layer By Attribute followed by Calculate Field. My preference is usually arcpy, but there are other geoprocessing ways of accomplishing the same task.

def removeName(shapefilePath):
    arcpy.MakeFeatureLayer_management(shapefilePath, "shapefileLayer",
                                      ' "NAME" LIKE \'***%\' ')
    arcpy.CalculateField_management("shapefileLayer", "NAME", "str()", "PYTHON_9.3")