topic Re: Add Field then Set the Field Value? in Python Questions

Add Field then Set the Field Value?

RobertStewart — Mon, 30 Jul 2012 18:20:07 GMT

I have a python script in which the end result is a single polygon in a file geodatabase that is added to the current map view. That part works fine.

What I want to do is create 2 new fields and set the values in those fields to be two parameters set in the original run of the tool (getparametersastext).

For example, would like to create two new fields: ZFile and Planner
Then set those fields to be equal to the parameters set manually at the start of the tool: Zfile and Planner

I've successfully created the fields, but I've had no success at setting the values for either.

As I mentioned, there is only one row in the dataset. I can set it manually, but the idea is to automate all of this.

Any points in the right direction are gratefully accepted.

Cheers!

Re: Add Field then Set the Field Value?

ChrisSnyder — Sat, 11 Dec 2021 08:52:31 GMT

It'd look something like this:

myFC = arcpy.GetParameterAsText(0)
var1 = arcpy.GetParameterAsText(1)
var2 = arcpy.GetParameterAsText(2)
arcpy.AddField_management(myFC, "FIELD1", "SHORT")
arcpy.AddField_management(myFC, "FIELD2", "SHORT")
arcpy.CalculateField_managment(myFC, "FIELD1", int(var1), "PYTHON")
arcpy.CalculateField_managment(myFC, "FIELD2", int(var2), "PYTHON")

Re: Add Field then Set the Field Value?

RobertStewart — Tue, 31 Jul 2012 14:53:25 GMT

Thanks!

This is pretty much exactly what I had, except the parameters are text. int() is for integer is it not?

No matter what I seem to have used, the values stay at <Null>

The nice thing is that this confirms that I was on the right track. I'm looking through python string functions as we speak.

Cheers!

Re: Add Field then Set the Field Value?

ChrisSnyder — Sat, 11 Dec 2021 08:52:33 GMT

As the name implies the arcpy.GetParameterAsText() method always brings values from the toolbox GUI into the script as string values. Three Python functions I use all the time:

convert to interger: int(myVariable)
convert to float: float(myVariable)
convert to string: str(myVariable)

Variables must be of the same type to do math operations or string concatenation. For example:

buffDist = arcpy.GetParameterAsText(0)
newBuffDist = float(buffDist) / 3.14159
arcpy.Buffer_analysis(myFC, myBuffFC, str(newBuffDist) + " METERS")

Re: Add Field then Set the Field Value?

RobertStewart — Tue, 31 Jul 2012 15:44:09 GMT

Wow, when trying to self-teach, the simplest things escape me.
I will be keeping those notes close at hand, we do a lot of that here. Thanks for that!

However, I still seem to be getting errors. Let me write out the variables and maybe this will be more clear:

ZFile = arcpy.GetParameterAsText(0) - Entered in the toolbox as: "Z-12-1234"
Planner = arcpy.GetParameterAsText(1) - Entered into the toolbox as: "XX"

I want to pass these values into a featureclass that was created via the same script, into a field called: "ZFile" and "Planner" (respectively).

arcpy.CalculateField_management("MyFC","ZFile",int(ZFile),"PYTHON")

The int(Zfile) expression returns an invalid literal. I'm too new at this to understand what that means.

I 'do' appreciate the help on this. I think I'm awfully close to the end.....

Re: Add Field then Set the Field Value?

ChrisSnyder — Sat, 11 Dec 2021 08:52:37 GMT

Sorry - leave off the int() part in the CalculateField tool. No sense in converting your character string to an integer! I was under the assumption your input values were integers. Not sure why I was thinking that...

This should work:

myFC = arcpy.GetParameterAsText(0)
var1 = arcpy.GetParameterAsText(1)
var2 = arcpy.GetParameterAsText(2)
arcpy.AddField_management(myFC, "FIELD1", "SHORT")
arcpy.AddField_management(myFC, "FIELD2", "SHORT")
arcpy.CalculateField_managment(myFC, "FIELD1", "'" + var1 + "'", "PYTHON")
arcpy.CalculateField_managment(myFC, "FIELD2", "'" + var2 + "'", "PYTHON")

Re: Add Field then Set the Field Value?

RobertStewart — Tue, 31 Jul 2012 18:11:29 GMT

Hmmm. Still not working. Posted below is my code. I feel like this should have worked. I had forgotten about the quotes within quotes bit.

In modelbuilder, I was forced to use '%Variable%'. Could that be it? (yes, I'm going to have a go at it...)

I did try setting the field type alternatively to "SHORT" and "TEXT", but neither made a difference. The fields get created but not populated.

Zfile and Planner variables are set by the tool GUI.

I feel like trying to create a fully automated, fully dynamic script was maybe NOT the best idea for my first delve into python....

----

df = arcpy.mapping.ListDataFrames(mxd, "PLOCMain")[0]
addLayer = arcpy.mapping.Layer(SaveFile)
arcpy.mapping.AddLayer(df, addLayer, "TOP")

arcpy.AddField_management(addLayer,"ZFile","TEXT")
arcpy.AddField_management(addLayer, "Planner","TEXT")

arcpy.CalculateField_managment(addLayer, "ZFile", "'" + ZFile + "'", "PYTHON")
arcpy.CalculateField_managment(addLayer, "Planner", "'" + Planner + "'", "PYTHON")

Re: Add Field then Set the Field Value?

RobertStewart — Tue, 31 Jul 2012 19:02:23 GMT

.....

And now I 'fully' realize why copying and pasting script is a better idea than writing my own....

arcpy.CalculateField_managEment()......

Sigh.

The last (corrected) script now produces blank fields as opposed to <Null>. I consider that a sign of improvement.

Re: Add Field then Set the Field Value?

ChrisSnyder — Tue, 31 Jul 2012 22:01:12 GMT

Yes, it'd be good to change the field types to text...

How about this:

myFC = arcpy.GetParameterAsText(0) var1 = arcpy.GetParameterAsText(1) var2 = arcpy.GetParameterAsText(2) arcpy.AddField_management(myFC, "FIELD1", "TEXT", "", "", "50") arcpy.AddField_management(myFC, "FIELD2", "TEXT", "", "", "50") arcpy.CalculateField_managment(myFC, "FIELD1", "'" + var1 + "'", "PYTHON") arcpy.CalculateField_managment(myFC, "FIELD2", "'" + var2 + "'", "PYTHON")

an alternate way using an update cursor:

myFC = arcpy.GetParameterAsText(0) var1 = arcpy.GetParameterAsText(1) var2 = arcpy.GetParameterAsText(2) arcpy.AddField_management(myFC, "FIELD1", "TEXT", "", "", "50") arcpy.AddField_management(myFC, "FIELD2", "TEXT", "", "", "50") updateRows = arcpy.UpdateCursor(myFC) for updateRow in updateRows:     updateRow.FIELD1 = var1     updateRow.FIELD2 = var2     updateRows.updateRow(updateRow) del updateRow, updateRows

If this aint working.... I dunno...

Are you sure your toolbox script tool is pointing to the correct script?

Re: Add Field then Set the Field Value?

RobertStewart — Wed, 01 Aug 2012 13:19:12 GMT

Indeed a good question, but yes, it is pointed correctly.

The script runs perfectly now, if I copy and paste it into a python window in ArcMap. This means I need to set the variables in the script instead of by the GUI.

Through the GUI/Toolbox, however, nothing seems to want to make the fields populate (they are blank instead of <Null>).

I sincerely thank you for helping me with this. For the sake of sanity, I may try simply have to manually enter those values into each map. Not the end of the world.

Cheers!

Re: Add Field then Set the Field Value?

ChrisSnyder — Sat, 11 Dec 2021 08:52:39 GMT

Okay one last stab... Note the #comments...

import arcpy
arcpy.SetProduct("ArcInfo") #or whatever lic level you are using
myFC = arcpy.GetParameterAsText(0) #IMPORTANT: In the toolbox GUI, this parameter should be a type of 'FeatureLayer'
var1 = arcpy.GetParameterAsText(1) #Toolbox type of 'String'
var2 = arcpy.GetParameterAsText(2) #Toolbox type of 'String'
arcpy.AddField_management(myFC, "FIELD1", "TEXT", "", "", "50")
arcpy.AddField_management(myFC, "FIELD2", "TEXT", "", "", "50")
updateRows = arcpy.UpdateCursor(myFC)
for updateRow in updateRows:
    updateRow.FIELD1 = var1
    updateRow.FIELD2 = var2
    updateRows.updateRow(updateRow)
del updateRow, updateRows

Re: Add Field then Set the Field Value?

RobertStewart — Sat, 11 Dec 2021 08:52:42 GMT

I double checked what the Toolbox variables were set at, and they seem to be correct. However, it did make me think that perhaps I'm doing something wrong somewhere else that's causing this to fail.

The code works 'except' that last copy of the data into the fields. And that, after all this, is minor. Feel free to point out the mistakes etc if you feel like it, critical advice is always welcome. It's my first real attempt at python.

Thanks for all your help. I wouldn't have gotten as far as I did without your help.

Cheers!

import arcpy,
from arcpy import env
arcpy.SetProduct("ArcInfo")
#Setting the workspace
arcpy.env.workspace = "I:\GIS\Mapping_GIS.gdb"
try:
    # Overwrite pre-existing files
    arcpy.env.overwriteOutput = True

    # Get the input values from the toolbox
    strtnum = arcpy.GetParameterAsText(0)#street number
    strtnam = arcpy.GetParameterAsText(1)#street name
    ZFile = arcpy.GetParameterAsText(2)#This is a file number like Z-00-0000
    Planner = arcpy.GetParameterAsText(3) #Usually initials
        
    FileName = strtnam + "_" + strtnum
    SaveFile = "I:\\GIS\\Mapping_GIS.gdb\\" + FileName

    ParcelTempLayer = "I:\\GIS\\Mapping_GIS.gdb\\ParcelTempLayer"
    AMANDA_PROPERTY = "Database Connections\\Amanda Connection to pama.sde\\AMANDA.PROPERTY"
    SDE_Parcels = "Database Connections\\Planning Connection to ctbgis.sde\\SDE.Planning\\SDE.Parcels"

    print "variables set"

    #Sets the map document to be the current one open
    mxd = arcpy.mapping.MapDocument("CURRENT")
   
    print "mxd set. Creating ParcelTempLayer - a layer file of SDE_Parcels"

    #Makes a layer from the SDE_Parcels data saves it under the parceltemplayer variable
    arcpy.MakeFeatureLayer_management(SDE_Parcels, ParcelTempLayer)

    print "ParcelTempLayer created. Creating AMANDA TableView"

    #Makes a table view from the AMANDA property records
    PROPNAM = "PROPNAM"
    arcpy.MakeTableView_management(AMANDA_PROPERTY, PROPNAM, "")

    print "AMANDA TableView created. Joining Table to Layer"

    #Joins the SDE_Parcels and PROPNAM
    arcpy.AddJoin_management(ParcelTempLayer, "PCL_PIN", "PROPNAM", "PROPGISID1", "KEEP_COMMON")
    print "Joined. Now extracting selection"

    expression = "PROPHOUSE = '" + strtnum + "' AND PROPSTREET = '" + strtnam + "'"

    #selects data

    print "Using this: " + expression

    arcpy.Select_analysis(ParcelTempLayer, SaveFile, expression)

    df = arcpy.mapping.ListDataFrames(mxd, "PLOCMain")[0]
    addLayer = arcpy.mapping.Layer(SaveFile)
    arcpy.mapping.AddLayer(df, addLayer, "TOP")

    arcpy.AddField_management(addLayer,"ZFile", "TEXT", "", "", "15")
    arcpy.AddField_management(addLayer, "Planner", "TEXT", "", "", "5")

    arcpy.CalculateField_management(addLayer, "ZFile", "'" + ZFile + "'", "PYTHON")
    arcpy.CalculateField_management(addLayer, "Planner", "'" + Planner + "'", "PYTHON")
    
    updateRows = arcpy.UpdateCursor(addLayer)
    for updateRow in updateRows:
        updateRow.ZFile = ZFile
        updateRow.Planner = Planner
        updateRows.updateRow(updateRow)
    del updateRow, updateRows
    del mxd, addLayer

    print "Complete"

   
except Exception, e:

   import traceback, sys
   tb = sys.exc_info()[2]
   print "Line %i" % tb.tb_lineno
   print e.message

del strtnam
del strtnum
del ZFile
del Planner
del PROPNAM
#del PROPNUM

del ParcelTempLayer
del SaveFile
del FileName
del AMANDA_PROPERTY
del SDE_Parcels
print "variables deleted"

Re: Add Field then Set the Field Value?

RobertStewart — Thu, 02 Aug 2012 14:55:01 GMT

That was confirmed.

Removing the try/except statements and dedenting it made the script work perfectly (using the updatecursor commands, NOT the calculatefield cammand).

Cheers!