centos7 安装pip+python3.6以及pip安装错误解决办法

Centos7安装pip

1.执行:yum install python-pip

若没有python-pip包，先执行：yum -y install epel-release，再执行yum install python-pip

2.pip install --upgrade pip

centos默认安装了python2.7

1.mkdir /usr/local/python3

3.安装依赖包：

yum -y groupinstall "Development tools"

安装的时候可能安装不上，或者其他什么问题，可以通过更换源来解决
Linux(CentOS7.1)修改默认yum源为国内的阿里云yum源
下载wget
yum install wget -y
echo 备份当前的yum源
mv /etc/yum.repos.d /etc/yum.repos.d.backup4comex
echo 新建空的yum源设置目录
mkdir /etc/yum.repos.d
echo 下载阿里云的yum源配置
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
然后重建缓存：
yum clean all
yum makecache

yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

4.在/usr/local/python3目录下

wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz

tar -xvf  Python-3.6.2.tar.xz
cd Python-3.6.2
./configure --prefix=/usr/local/python3
make && make install

5.切换到/usr/bin/目录下

mv python python.bak
mv pip pip.bak
ln -s /usr/local/python3/bin/python3 /usr/bin/python
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip

6.防止以后用yum源安装软件时报错,修改以下两项

修改 /usr/bin/yum 的第一行

#!/usr/bin/python改成#!/usr/bin/python2.7

修改 /usr/libexec/urlgrabber-ext-down的第一行

#!/usr/bin/python改成#!/usr/bin/python2.7

7.验证

输入python，进入python3.6.2

输入python2，进入python2.7

8、这里还有一个问题是在使用pip安装模块的时候经常会报错

[ Python-3.6.2]# pip install ipython==1.2.1
Collecting ipython==1.2.1
Could not fetch URL https://pypi.python.org/simple/ipython/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748) - skipping
Could not find a version that satisfies the requirement ipython==1.2.1 (from versions: )
No matching distribution found for ipython==1.2.1

这是因为ssl证书没有认证，可以使用国内的镜像

pip install ipython==1.2.1 -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com

其中ipython是包的名字,这样即可解决。