擅长:python、mysql、java
<p>这是一种方式。您可以删除重复项并构建组合格式。然后通过<code>code</code>映射到原始数据帧</p>
<pre><code>df2 = df.drop_duplicates('code')
df2['comb'] = df2['code'] + '_' + df2['type'] + '_' + df2['note']
df['code'] = df['code'].map(df2.set_index('code')['comb'])
df = df[['pid', 'code']]
# pid code
# 0 1 A_M_alvedon
# 1 1 B_D_pain
# 2 1 C_M_ulcer
# 3 2 A_M_alvedon
# 4 2 B_D_pain
# 5 3 A_M_alvedon
# 6 3 B_D_pain
# 7 3 C_M_ulcer
# 8 4 A_M_alvedon
# 9 4 B_D_pain
# 10 5 A_M_alvedon
# 11 5 B_D_pain
</code></pre>