如果一列中有一个相同的值，如何将两行合并为一行并更改列名

import pandas as pd

data = {'列名1': ['值1', '值2'],
        '列名2': ['值3', '值4'],
        '列名3': ['值5', '值6']}
df = pd.DataFrame(data)

df_merged = df.groupby('列名1').agg(lambda x: ' '.join(x)).reset_index()

df_merged.columns = ['新列名1', '新列名2', '新列名3']

import pandas as pd

data = {'列名1': ['值1', '值2'],
        '列名2': ['值3', '值4'],
        '列名3': ['值5', '值6']}
df = pd.DataFrame(data)

df_merged = df.groupby('列名1').agg(lambda x: ' '.join(x)).reset_index()
df_merged.columns = ['新列名1', '新列名2', '新列名3']

print(df_merged)

  新列名1 新列名2 新列名3
0    值1    值3    值5
1    值2    值4    值6