擅长:python、mysql、java
<p>我根据一些假设修改了你的代码。我想你要做的是用你的面具蒙版成原始的测向图,打印或求和,另外得到长度。要获得原始df使用掩码所需的长度,请调用<code>dropna()</code>删除<code>NaN</code>行,然后对结果df调用<code>len</code>:</p>
<pre><code>In [16]:
year=np.array([1851.203,1851.632,1851.969,1851.975,1852.314,1852.347,1852.358,1852.385,1852.977,1853.196,1853.229,1853.319,1853.5,1854.135,1856.396,1856.506,1856.539,1856.618,1857.138,1857.404])
coal=pd.DataFrame(year)
def disaster(year1,year2):
total = (coal >= year1) & (coal <= year2)
print (coal[total].sum())
print(len(coal[total].dropna()))
disaster(1852,1856)
0 18529.76
dtype: float64
10
</code></pre>