擅长:python、mysql、java
<p>我想出来了:</p>
<pre><code>def new_value(column_1,column_2, column_3):
if column_1 == 'C':
return column_2[:]
elif column_1 == 'G':
return column_3[:]
else:
return 'NaN'
df1['column_new'] = df1.apply(lambda row: new_value(row.column_1, row.column_2, row.column_3), axis = 1)
</code></pre>