擅长:python、mysql、java
<pre class="lang-py prettyprint-override"><code>import pandas
import numpy
x = numpy.arange(1,24000)
months = pandas.DataFrame(pandas.date_range('2021-01-01', '2022-01-01', freq='M'))
projects = pandas.DataFrame(x)
%time projects_status = projects.merge(pandas.DataFrame(months), how='cross')
#CPU times: user 25.8 ms, sys: 2.54 ms, total: 28.3 ms
#Wall time: 35.9 ms
</code></pre>