Identify and delete all unrequired fields from Shapefile using ArcPy

Question

I have some Shapefiles inside one Folder and for the sake of data compression I want to delete all fields from Table of Content that can be removed (that are not required)!

What I have:

What I expect:

My code that is not working:

import arcpy
import os

arcpy.env.workspace = r"C:\Temp\"
fcList = arcpy.ListFeatureClasses()

for fc in fcList:
    fields = arcpy.ListFields(fc)
    for field in fields:
        delFlds = [field for field in fields if field != "FID" or field != "Shape"]
        arcpy.DeleteField_management(fc, delFlds)

I am using Python 2.7 and ArcMap 10.4.1

Answer 1

You are listing field objects with ListFields, not the field names which should be input to DeleteField. So change:

[field for field in fields if field != "FID" or field != "Shape"]

to:

[field.name for field in fields if field.name not in ("FID","Shape")]

But it is probably better to use the required property since object id and shape fields can have different names in different feature classes:

for fc in fcList:
    fields_to_delete = [field.name for field in arcpy.ListFields(fc) if not field.required]
    fields_to_delete.pop() #Keep one non-required field
    for field in fields_to_delete:
        arcpy.DeleteField_management(fc, field)

Answer 2

I usually make an explicit list of fields I want to keep, then loop through and delete any others. I don't remember where I saw this method originally, but it could have come from this discussion about keeping only certain fields.

I do like @BERA's use of field.required and would suggest using that - though I've historically listed OBJECTID, FID, SHAPE, etc. explicitly.

So for example, if you needed to keep only a field called DIMENSION and a field called RESPONSIBLE_PARTY:

keep_fields = ["DIMENSION","RESPONSIBLE_PARTY"]

fieldNameList = []
fieldObjList = arcpy.ListFields(table)

for field in fieldObjList:
    if (not field.name in keep_fields) and (not field.required):
        fieldNameList.append(field.name)

arcpy.DeleteField_management(table,fieldNameList)