Adding input field to field map using ArcPy gives RuntimeError

Question

I'm a Python beginner and I would like to export a csv from a feature class, including only some fields. I'm trying to do it using the field mapping control, but I'm doing something wrong because I have the following error: RuntimeError: FieldMap: Error in adding input field to field map

here the code:

outPathTable = r"output_path"       #get parameter as text
myFc = r'myFc_path'                 #get parameter as text
outName = myFc + "_dataQualityFc.csv"
List of fields to keep
outputFields = ['MemberID_target',
                         'PersonalID_target',
                         'Latitude', 
                         'Longitude', 
                         'dataQualityRisk_sameCH',
                          'dataQualityRisk_diffCH']
fieldMappings = arcpy.FieldMappings()
Create the field mappings from the outputField list
only fields in the list will be inlcuded in the exported file
for field in outputFields:
    fieldMap = arcpy.FieldMap()
    fieldMap.addInputField(myFc, field)
    fieldMappings.addFieldMap(fieldMap)
Create a csv for Data Quality Risk using the field mapping
arcpy.TableToTable_conversion(myFc, outPathTable, outName, "", fieldMappings)

score 1 · Answer 1 · edited May 01 '21 at 07:12

Here's how I did it:

Set up the field mappings object
Set up a nested Python dictionary with details on the fields I wanted
Looped through that to add each individual field mapping
Then the field mappings object could be used in the TableToTable_conversion

Kudos to this answer to Using Field Mapping with TableToTable_conversion in arcpy for leading me down the right path for loop in #3

fms = arcpy.FieldMappings()
fieldMappingDict = {
    1: {'fieldName':'ID','fieldType':'Text','fieldLength':8},
    2: {'fieldName':'Name','fieldType':'Text','fieldLength':128},
    3: {'fieldName':'Address1','fieldType':'Text','fieldLength':128},
    4: {'fieldName':'City','fieldType':'Text','fieldLength':64},
    5: {'fieldName':'Zip','fieldType':'Text','fieldLength':12},
    6: {'fieldName':'Phone','fieldType':'Text','fieldLength':18},
   ....
    }
#Loop through the mapping dictionary and set up individual field mappings to add to the fms
for cid, columnDef in fieldMappingDict.items():
    fm = arcpy.FieldMap()
    fm.addInputField(inTable,columnDef['fieldName'])
    newField = fm.outputField
    newField.type = columnDef['fieldType']
    newField.length = columnDef['fieldLength']
    fm.outputField = newField
    fms.addFieldMap(fm)

Adding input field to field map using ArcPy gives RuntimeError

List of fields to keep

Create the field mappings from the outputField list

only fields in the list will be inlcuded in the exported file

Create a csv for Data Quality Risk using the field mapping

1 Answers1