擅长:python、mysql、java
<p>尝试格式化列和groupby以及新的数据框和<code>concat</code>和<code>drop</code>:</p>
<pre><code>v = df.groupby('ROLLNO').apply(lambda x: x.values.tolist())
df = pd.DataFrame(v.tolist(), index=v.index)\
.rename(columns=lambda x: x + 1)\
.add_prefix('G')\
.reset_index()
df1 = pd.DataFrame(df['G1'].values.tolist())
df2 = pd.DataFrame(df['G2'].values.tolist())
df = pd.concat([df['ROLLNO'], df1, df2], axis=1)
df.columns=df.columns.astype(str)
df=df.drop(['0','6'],1)
df.columns = [df.columns[0]] + [f'G{i+1}' for i in range(len(df.columns)-1)]
print(df)
</code></pre>