script_tool_add_fields.py

# Name: Ulrich Stroetz (U102778)
# Date: 2/17/2013
# Purpose: Add fields

# Import system modules
import arcpy

# Input Feature Class) 
inputFC = arcpy.GetParameterAsText(0)

# Create list of field names
inputString = arcpy.GetParameterAsText(1)
fieldListNew = inputString.split(";")
fieldType = arcpy.GetParameterAsText(2)
fieldListExist = [f.name for f in arcpy.ListFields(inputFC)]

# Add fields
for fieldName in fieldListNew:
    # Check if it already exists
    if fieldName in fieldListExist:
        arcpy.AddMessage("The field %s already exists and will not be created." % fieldName)

    # If not, add it
    else: 
        fieldName_new = arcpy.ValidateFieldName(fieldName) 
        if fieldName_new != fieldName:
            arcpy.AddMessage(fieldName + " becomes " + fieldName_new)
        arcpy.AddField_management(inputFC , fieldName_new, fieldType)
        arcpy.AddMessage("Created field:" + fieldName_new)
    
arcpy.AddMessage ("Process completed")