pip安装Python第三方库时MemoryError的解决方法

pip安装Matplot库时遇到MemoryError的错误，类似以下的提示信息。

File
“/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/filewrapper.py”,
line 54, in read
self.__callback(self.__buf.getvalue())
File “/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/controller.py”,
line 205, in cache_response
self.serializer.dumps(request, response, body=body),
File “/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/serialize.py”,
line 81, in dumps
).encode(“utf8”), MemoryError” File “/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/serialize.py”,
line 81, in dumps
).encode(“utf8”), MemoryError”

查找到是由于pip的缓存机制尝试将希望安装库的整个文件缓存到内存，而在限制缓存大小的环境中如果安装包较大就会出现MemoryError的这个错误。
解决方法:

$ pip --help
......省略......
--client-cert         Path to SSL client certificate, a single file
                            containing the private key and the certificate
                            in PEM format.
--cache-dir            Store the cache data in .
--no-cache-dir              Disable the cache.
--disable-pip-version-check
                            Don't periodically check PyPI to determine
                            whether a new version of pip is available for
                            download. Implied with --no-index.

可以看到pip有个–no-cache-dir参数，失能缓冲即可。

$pip --no-cache-dir install matplotlib