擅长:python、mysql、java
<p>下面是如何组合来自年度数据帧的数据。假设每年的数据帧以某种方式存储在字典中:</p>
<pre><code>df = {2000: ..., 2001: ..., ..., 2008: ...}
yearly = []
for N in df.keys():
tmp = df[N].pivot('Country','Gender','Total').fillna(0).astype(int)
tmp['Year'] = N # Store the year
tmp['totmigrants'] = tmp['M'] + tmp['F']
yearly.append(tmp)
df = pd.concat(yearly)
print(df)
#Gender F M Year totmigrants
#Country
#Afghanistan 3 70 2000 73
#Albania 6 5 2000 11
#Algeria 0 44 2000 44
#Zimbabwe 1 0 2000 1
</code></pre>
<p>现在可以使用<code>['Country','Year']</code>作为键将<code>df</code>与第一个数据帧合并。在</p>