I have a company laptop which is behind a company HTTP proxy. It takes me lots of time to study how to use proxy for pip. At beginning, I tried "pip search --proxy xxx.xxx.xx.xx:xxxx matplotlib", but it doesn't work. Then I searched internet and found there are some bugs in pip proxy, like link,NTLM proxy issue. I even tried to use privoxy to convert socket5 proxy from ssh to HTTP to fix them, but it still doesn't work.