NumPy经典20题
https://mp.weixin.qq.com/s?__biz=MzI0ODcxODk5OA==&mid=2247521644&idx=3&sn=fc77a295a88311e062208969f990e984&chksm=e99ea695dee92f83d9f444853eb373d1ba6fb6c6ff79eb48241b72da14ba64d95a3e55b82ffa&mpshare=1&scene=23&srcid=0720jspG95FL5jeYfIULA0Ql&sharer_sharetime=1595241204446&sharer_shareid=30031d9d29159117fee606b42f967444#rd