How to check if feature class or table contains field with specific name before adding it?

Question

Im trying to write a script that finds out if the shapefile has a specific field and if not to add the field. I get it to show me the field, but the loop goes through each field, so it would create a new field each time the specified field is not there. But if it's theres I just want it to say it is there and if it's not to create new field. My code so far just says:

"not filled in yet"
"not filled in yet"
"not filled in yet"
"cities.shp"
"not filled in yet"

(prints out like this cause there are five fields)

My code so far:

fieldList = arcpy.ListFields("cities.shp")

for field in fieldList:

if field.name == "CAPITAL":
    print "cities.shp"

else: 
    "then add new field"

Answer 1

Instead of looping over the current field names, you can loop over the field names you want to add. Let's say you have a list, to_add, containing the field names you want your feature class to have. You can then use the in statement to check if each item from to_add is in fieldList. The following should work:

#List of field names to be added
to_add = ["Area", "Date_add", "User_add", "etc."]

#Create a list of existing field names
fieldList = arcpy.ListFields("cities.shp")    
fieldName = [f.name for f in fieldList]

for field in to_add:
  if field in fieldName:
    print "Already exists!"
  else:
    arcpy.AddField_management("cities.shp", field, "TEXT")