回答此问题可获得 20 贡献值,回答如果被采纳可获得 50 分。
<p>我使用的是python3.6.4和pandas0.23.0。我已经为构造函数和附加引用了pandas 0.23.0文档。它没有提到任何不存在的价值观。我没有发现任何类似的例子。你知道吗</p>
<p>考虑以下代码:</p>
<pre><code>import pandas as pd
months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
index_yrs = [2016, 2017, 2018]
r2016 = [26, 27, 25, 22, 20, 23, 22, 20, 20, 18, 18, 19]
r2017 = [20, 21, 18, 16, 15, 15, 15, 15, 13, 13, 14, 15]
r2018 = [16, 18, 18, 18, 17]
df = pd.DataFrame([r2016], columns = months, index = [index_yrs[0]])
df = df.append(pd.DataFrame([r2017], columns = months, index = [index_yrs[1]]))
</code></pre>
<p>现在如何添加r2018,只有5月份的数据?你知道吗</p>