# rename Pandas columns to lower case
df.columns= df.columns.str.lower()
df.columns
Index(['column1', 'column2', 'column3'], dtype='object')
# Creating 'columnB' that has Uppercase versions of all of columnA's values
df['columnB'] = df['columnA'].str.upper()
data.columns = [x.lower() for x in data.columns]
data.columns = map(str.lower, data.columns)