Python script- changing layer's name

[MalgorzataMendela]

Hello, I do not know why the following python script does not work and cause a change of the layer's name (from 'States' to 'Stany'). After running the script I have received the message:" script returned exit code 0". Any suggestions? Thank you.

import arcpy.mapping

mxd = arcpy.mapping.MapDocument("F:/DSW/Using_ArcGIS_Desktop/MexicoPopulationDensity.mxd")

for df in arcpy.mapping.ListDataFrames(mxd):

    if (df.name == 'States'):

        layers = arcpy.mapping.ListLayers(mxd,'Stany',df)

[MalgorzataMendela]

Yes, I have read this link, but I could not find there the answer to my problem. This is the layout view:

[AnthonyFarndon]

As Joshua says, your df name is wrong.

I would use something like

df = arcpy.mapping.ListDataFrames(mxd, "")[0] or df = arcpy.mapping.ListDataFrames(mxd, "Mexico")[0]

and then no need for if df,name == , just use

layers = arcpy.mapping.ListLayers(mxd,'states',df)

[MalgorzataMendela]

Thank you Anthony for your message.
I have changed my code into the following;

import arcpy.mapping

mxd = arcpy.mapping.MapDocument("CURRENT")

df=arcpy.mapping.ListDataFrames(mxd,"Mexico")[0]

layers = arcpy.mapping.ListLayers(mxd,'states',df)
but there is nothing about changing the name of a feature class from 'states' to 'stany', so the result is still the same...
Don't I need to use for..if clause in order to change the name of a feature class?

[AnthonyFarndon]

Like a lot of things, there are many ways to achieve what you want.

layers = arcpy.mapping.ListLayers(mxd,'states',df)

will return a list of all layers named states, so you could loop through it to change the name

for lyr in layers:

    lyr.name = "stany"

However if there is only one layer likely to be called states in the mxd, a shorthand way of achieving this is

lyr = arcpy.mapping.ListLayers(mxd,'states',df)[0]

lyr.name = "stany"

Doing an if == is useful if you are wanting to loop through many layers of differing names. eg

layers = arcpy.mapping.ListLayers(mxd,'',df)

for lyr in layers:

    if lyr.name == "states":

        lyr.name = "stany"

    elif lyr.name == "Lakes":

        lyr.name = "Lakey"

or to do more complex 'stuff' with name matches than the ListLayers wildcard parameter allows, such as ignoring case.

if lyr.name.lower() == "states":

Finally, if you are doing this with the mxd open, add in the following to see the changes on screen

arcpy.RefreshTOC()

And save the mxd if required

mxd.save()

[MalgorzataMendela]

Thank you very much for your help

[JoshuaBixby]

Please mark Anthony's response Correct if it answered your question.  That way, it lets others know the question has been answered.