Generate unique index from existing nonunique index pandas

I have a pandas DataFrame with an index like this:

foo
bar
spam
eggs
foo
bar
spam
eggs

I can access values by using df.loc['foo', 'column'][0], but if I try to set values in the way I get a SettingWithCopyWarning. I need to keep the word descriptions in the index, so is there a way of generating a new index that looks like this?:

foo
bar
eggs
spam
foo_1
bar_1 ... etc.

>Solution :

Check groupby with cumcount

df.index += df.groupby(level=0).cumcount().mask(lambda x : x==0,'').astype(str)