擅长:python、mysql、java
<p>你可以这样做</p>
<pre class="lang-py prettyprint-override"><code>country_list = df.Country.unique().tolist()
df.drop(columns = ['Code'])
df_2016 = df.loc[(df['Country'].isin(country_list))&(df['Year']==2016)].reset_index()
df_2000 = df.loc[(df['Country'].isin(country_list))&(df['Year']==2000)].reset_index()
df_2016.drop(columns=['Year'])
df_2000.drop(columns=['Year'])
df_2016.set_index('Country').subtract(df_2000.set_index('Country'), fill_value=0)
</code></pre>