0x00 pip的环境问题

在安装scikit-learn等科学计算包时，经常会遇到下载超时或依赖冲突的问题。以下记录常见解决方案。

0x01 pip-timeout

设置default-timeout参数避免下载超时：

安装scikit-learn依赖包，安装时一直报错time out超时，所以加上了default-timeout参数：

pip3 --default-timeout=1000 install -U scikit-learn
 Downloading https://pypi.tuna.tsinghua.edu.cn/packages/73/db/7d8204ddba84ab5d1e4fd1af8f82bbe39c589488bee71e45c662f4144010/scikit_learn-0.22.1-cp37-cp37m-manylinux1_x86_64.whl (7.0MB)
    100% |████████████████████████████████| 7.0MB 159kB/s 
Successfully installed scikit-learn-0.22.1

pip3 --default-timeout=1000 install -U SciPy
Downloading https://pypi.tuna.tsinghua.edu.cn/packages/dd/82/c1fe128f3526b128cfd185580ba40d01371c5d299fcf7f77968e22dfcc2e/scipy-1.4.1-cp37-cp37m-manylinux1_x86_64.whl (26.1MB)
    100% |████████████████████████████████| 26.1MB 44kB/s 
Successfully installed SciPy-1.4.1

0x02 国内换源

pip默认源在国外，下载速度慢。配置国内镜像源：

Linux/macOS

vi ~/.pip/pip.conf

[global]
timeout = 6000
index-url = https://pypi.tuna.tsinghua.edu.cn/simple/

Windows

# 进入C:\Users\用户名\pip，在pip目录下新建文件
# pip.ini，填入同样内容

常用国内镜像源

镜像 地址
清华 https://pypi.tuna.tsinghua.edu.cn/simple/
阿里云 http://mirrors.aliyun.com/pypi/simple/
中科大 https://pypi.mirrors.ustc.edu.cn/simple/
豆瓣 http://pypi.douban.com/simple/

0x03 验证

# pip install pandas
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Requirement already satisfied: pandas in /usr/local/lib/python2.7/dist-packages (0.24.2)
Requirement already satisfied: pytz>=2011k in /usr/lib/python2.7/dist-packages (from pandas) (2019.3)
Requirement already satisfied: numpy>=1.12.0 in /usr/local/lib/python2.7/dist-packages (from pandas) (1.16.6)
Requirement already satisfied: python-dateutil>=2.5.0 in /usr/local/lib/python2.7/dist-packages (from pandas) (2.8.1)
Requirement already satisfied: six>=1.5 in /usr/lib/python2.7/dist-packages (from python-dateutil>=2.5.0->pandas) (1.14.0)