我下载了python3 package并安装它，我发现pip3也已安装。
aircraftdeMacBook-Pro:~ ldl$ which python3
aircraftdeMacBook-Pro:~ ldl$ which pip3
....there I install the .dmg for python3 I download from the upper link.
aircraftdeMacBook-Pro:~ ldl$ which python3
/usr/local/bin/python3
aircraftdeMacBook-Pro:~ ldl$ python3 --version
Python 3.5.2
aircraftdeMacBook-Pro:~ ldl$ which pip3
/usr/local/bin/pip3
所以，我想确认pip3包是否包含在.dmg文件中，因为安装python3时也会安装pip3。
从命令行可以看到我只安装了python3 dmg，但也安装了pip3。