<p>假设您的列表如下:</p>
<pre class="lang-py prettyprint-override"><code>this_list = [[0.001, 0.017000000000000001, 4.0, 75.0],
[5352984.0, 23194715.0, 8.0, 150.0],
[2370914.0, 11533745.0, 21.0, 396.0],
[0.39500000000000002, 0.68100000000000005, 68.0, 1296.0],
[0.46400000000000002, 0.69099999999999995, 69.0, 1307.0],
[0.0, 0.001, 12.0, 226.0],
[0.0, 0.001, 10.0, 194.0],
[0.055, 0.22600000000000001, 7.0, 136.0],
[0.055, 0.109, 10.0, 181.0],
[0.001, 0.037999999999999999, 29.0, 556.0],
[0.0030000000000000001, 0.14099999999999999, 46.0, 873.0],
[0.0, 1.0, 15.0, 287.0],
[0.0, 0.0, 6.0, 108.0],
[0.0, 0.0, 29.0, 556.0],
[0.0, 0.024, 46.0, 873.0],
[7086684.0, 68448914.0, 3.0, 53.0]]
</code></pre>
<p>你的“第三排”是这样的:</p>
<pre class="lang-py prettyprint-override"><code>[ 4., 8., 21., 68., 69., 12., 10., 7., 10., 29., 46., 15., 6., 29., 46., 3.]
</code></pre>
<p>然后你可以简单地:</p>
<pre class="lang-py prettyprint-override"><code>import numpy as np
np_list = np.array(this_list)
# sum in a new row
new_row = np.sum([np_list[:,2], np_list[:,3]], axis=0)
# sum each elements of the 3rd and 4rd rows separetadly
row3, row4 = np.sum([np_list[:,2], np_list[:,3]], axis=1)
</code></pre>