change the version of python on my centos

There are two versions of aconda: aconda and aconda3 in my home directorys.

When comment the environment path of aconda in the zshrc file and remain the path of aconda3, the python version is python 2.7. And vice versa.

the evironment is as follows:

# added by Anaconda3 4.1.0 installer: python 3
export PATH="/home/zyj/anaconda3/bin:$PATH"
export PATH="$HOME/.plenv/bin:$PATH"

#anaconda : python 2
#export PATH=/home/zyj/anaconda/bin:$PATH
#export PATH="$HOME/.plenv/bin:$PATH"
#eval "$(plenv init -)"