使用命令sudo pip3 install matplotlib已知報錯，用同樣的命令安裝numpy和opencv卻沒有，因此重裝linux系統兩次都沒有解決（我是在Vmware中創建的）。報錯如下：
rogn@ubuntu:~$sudo pip3 install matplotlib Collecting numpy Exception: Traceback (most recent call last): File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connection.py", line 137, in _new_conn (self.host, self.port), self.timeout, **extra_kw) File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/connection.py", line 91, in create_connection raise err File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/connection.py", line 81, in create_connection sock.connect(sa) OSError: [Errno 101] Network is unreachable During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 560, in urlopen body=body, headers=headers) File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 346, in _make_request self._validate_conn(conn) File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 787, in _validate_conn conn.connect() File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connection.py", line 217, in connect conn = self._new_conn() File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connection.py", line 146, in _new_conn self, "Failed to establish a new connection: %s" % e) requests.packages.urllib3.exceptions.NewConnectionError: <requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f3bbaa12198>: Failed to establish a new connection: [Errno 101] Network is unreachable During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/usr/lib/python3/dist-packages/pip/basecommand.py", line 209, in main status = self.run(options, args) File "/usr/lib/python3/dist-packages/pip/commands/install.py", line 328, in run wb.build(autobuilding=True) File "/usr/lib/python3/dist-packages/pip/wheel.py", line 748, in build self.requirement_set.prepare_files(self.finder) File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 360, in prepare_files ignore_dependencies=self.ignore_dependencies)) File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 512, in _prepare_file finder, self.upgrade, require_hashes) File "/usr/lib/python3/dist-packages/pip/req/req_install.py", line 273, in populate_link self.link = finder.find_requirement(self, upgrade) File "/usr/lib/python3/dist-packages/pip/index.py", line 442, in find_requirement all_candidates = self.find_all_candidates(req.name) File "/usr/lib/python3/dist-packages/pip/index.py", line 400, in find_all_candidates for page in self._get_pages(url_locations, project_name): File "/usr/lib/python3/dist-packages/pip/index.py", line 545, in _get_pages page = self._get_page(location) File "/usr/lib/python3/dist-packages/pip/index.py", line 648, in _get_page return HTMLPage.get_page(link, session=self.session) File "/usr/lib/python3/dist-packages/pip/index.py", line 757, in get_page "Cache-Control": "max-age=600", File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 480, in get return self.request('GET', url, **kwargs) File "/usr/lib/python3/dist-packages/pip/download.py", line 378, in request return super(PipSession, self).request(method, url, *args, **kwargs) File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 468, in request resp = self.send(prep, **send_kwargs) File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 576, in send r = adapter.send(request, **kwargs) File "/usr/share/python-wheels/CacheControl-0.11.5-py2.py3-none-any.whl/cachecontrol/adapter.py", line 46, in send resp = super(CacheControlAdapter, self).send(request, **kw) File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/adapters.py", line 376, in send timeout=timeout File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 610, in urlopen _stacktrace=sys.exc_info()[2]) File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 228, in increment total -= 1 TypeError: unsupported operand type(s) for -=: 'Retry' and 'int' You are using pip version 8.1.1, however version 19.0.3 is available. You should consider upgrading via the 'pip install --upgrade pip' command.
可能當時太沖動，沒有考慮太多網絡問題，仔細看報錯，第一個就是。
解決方法
網絡問題，解決方案很簡單，不用官方源改用阿里鏡像。命令如下：
sudo pip3 install matplotlib -i http://mirrors.aliyun.com/pypi/simple/ --trusted-host mirrors.aliyun.com
效果如下：
rogn@ubuntu:~$ sudo pip3 install matplotlib -i http://mirrors.aliyun.com/pypi/simple/ --trusted-host mirrors.aliyun.com The directory '/home/rogn/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag. The directory '/home/rogn/.cache/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag. Collecting matplotlib Downloading http://mirrors.aliyun.com/pypi/packages/ad/4c/0415f15f96864c3a2242b1c74041a806c100c1b21741206c5d87684437c6/matplotlib-3.0.2-cp35-cp35m-manylinux1_x86_64.whl (12.9MB) 100% |████████████████████████████████| 12.9MB 11.4MB/s Collecting kiwisolver>=1.0.1 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/7e/31/d6fedd4fb2c94755cd101191e581af30e1650ccce7a35bddb7930fed6574/kiwisolver-1.0.1-cp35-cp35m-manylinux1_x86_64.whl (949kB) 100% |████████████████████████████████| 952kB 27.3MB/s Collecting cycler>=0.10 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/f7/d2/e07d3ebb2bd7af696440ce7e754c59dd546ffe1bbe732c8ab68b9c834e61/cycler-0.10.0-py2.py3-none-any.whl Collecting pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/de/0a/001be530836743d8be6c2d85069f46fecf84ac6c18c7f5fb8125ee11d854/pyparsing-2.3.1-py2.py3-none-any.whl (61kB) 100% |████████████████████████████████| 71kB 14.8MB/s Requirement already satisfied (use --upgrade to upgrade): numpy>=1.10.0 in /usr/local/lib/python3.5/dist-packages (from matplotlib) Requirement already satisfied (use --upgrade to upgrade): python-dateutil>=2.1 in /usr/local/lib/python3.5/dist-packages (from matplotlib) Requirement already satisfied (use --upgrade to upgrade): setuptools in /usr/lib/python3/dist-packages (from kiwisolver>=1.0.1->matplotlib) Requirement already satisfied (use --upgrade to upgrade): six in /usr/lib/python3/dist-packages (from cycler>=0.10->matplotlib) Installing collected packages: kiwisolver, cycler, pyparsing, matplotlib Successfully installed cycler-0.10.0 kiwisolver-1.0.1 matplotlib-3.0.2 pyparsing-2.3.1 You are using pip version 8.1.1, however version 19.0.3 is available. You should consider upgrading via the 'pip install --upgrade pip' command.
就是網絡慢，有時候可以慢速下載，有時直接連接失敗， 好像科學上網也不行，不知道pip3的--timeout選項變大點會不會好點。（不吐槽了，換源大法好！
Windows下同樣的問題
當出現這一問題，我的Visual Studio 2017的Python3板塊下使用命令pip3 install matplotlib也出錯，報錯如下:
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python36_64>pip3 install matplotlib Collecting matplotlib Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ReadTimeoutError("HTTPSConnectionPool(host='pypi.org', port=443): Read timed out. (read timeout=15)",)': /simple/matplotlib/ Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ReadTimeoutError("HTTPSConnectionPool(host='pypi.org', port=443): Read timed out. (read timeout=15)",)': /simple/matplotlib/ Using cached https://files.pythonhosted.org/packages/b1/56/569c83515c10146fd0aa09e086816b12e301d0811048e3354a6e9b77ba9a/matplotlib-3.0.2-cp36-cp36m-win_amd64.whl Requirement already satisfied: numpy>=1.10.0 in c:\program files (x86)\microsoft visual studio\shared\python36_64\lib\site-packages (from matplotlib) (1.16.1) Collecting pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 (from matplotlib) Could not find a version that satisfies the requirement pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 (from matplotlib) (from versions: ) No matching distribution found for pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 (from matplotlib) You are using pip version 19.0.2, however version 19.0.3 is available. You should consider upgrading via the 'python -m pip install --upgrade pip' command.
同樣也是網絡問題，用上面同樣的方法：
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python36_64>pip install matplotlib -i http://mirrors.aliyun.com/pypi/simple/ --trusted-host mirrors.aliyun.com Looking in indexes: http://mirrors.aliyun.com/pypi/simple/ Collecting matplotlib Downloading http://mirrors.aliyun.com/pypi/packages/b1/56/569c83515c10146fd0aa09e086816b12e301d0811048e3354a6e9b77ba9a/matplotlib-3.0.2-cp36-cp36m-win_amd64.whl (8.9MB) 100% |████████████████████████████████| 8.9MB 11.4MB/s Collecting pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/de/0a/001be530836743d8be6c2d85069f46fecf84ac6c18c7f5fb8125ee11d854/pyparsing-2.3.1-py2.py3-none-any.whl (61kB) 100% |████████████████████████████████| 71kB 3.8MB/s Collecting cycler>=0.10 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/f7/d2/e07d3ebb2bd7af696440ce7e754c59dd546ffe1bbe732c8ab68b9c834e61/cycler-0.10.0-py2.py3-none-any.whl Requirement already satisfied: numpy>=1.10.0 in c:\program files (x86)\microsoft visual studio\shared\python36_64\lib\site-packages (from matplotlib) (1.16.1) Collecting python-dateutil>=2.1 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/41/17/c62faccbfbd163c7f57f3844689e3a78bae1f403648a6afb1d0866d87fbb/python_dateutil-2.8.0-py2.py3-none-any.whl (226kB) 100% |████████████████████████████████| 235kB 17.1MB/s Collecting kiwisolver>=1.0.1 (from matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/44/72/16630c3392eba03788ad87949390516bbc488e8e118047a3b824631d21a6/kiwisolver-1.0.1-cp36-none-win_amd64.whl (57kB) 100% |████████████████████████████████| 61kB 5.6MB/s Collecting six (from cycler>=0.10->matplotlib) Downloading http://mirrors.aliyun.com/pypi/packages/73/fb/00a976f728d0d1fecfe898238ce23f502a721c0ac0ecfedb80e0d88c64e9/six-1.12.0-py2.py3-none-any.whl Requirement already satisfied: setuptools in c:\program files (x86)\microsoft visual studio\shared\python36_64\lib\site-packages (from kiwisolver>=1.0.1->matplotlib) (40.8.0) Installing collected packages: pyparsing, six, cycler, python-dateutil, kiwisolver, matplotlib Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: 'c:\\program files (x86)\\microsoft visual studio\\shared\\python36_64\\Lib\\site-packages\\pyparsing.py' Consider using the `--user` option or check the permissions. You are using pip version 19.0.2, however version 19.0.3 is available. You should consider upgrading via the 'python -m pip install --upgrade pip' command.
附加：
- 阿里雲 http://mirrors.aliyun.com/pypi/simple/
- 中國科技大學 https://pypi.mirrors.ustc.edu.cn/simple/
- 豆瓣(douban) http://pypi.douban.com/simple/
- 清華大學 https://pypi.tuna.tsinghua.edu.cn/simple/
參考鏈接：https://blog.csdn.net/qq_25964837/article/details/80295041