CommandNotFoundError: Your shell has not been properly configured to use 'conda activate'. If your s

CommandNotFoundError: Your shell has not been properly configured to use 'conda activate'.
If your shell is Bash or a Bourne variant, enable conda for the current user with

    $ echo ". /Users/matthewspeck/anaconda3/etc/profile.d/conda.sh" >> ~/.bash_profile

or, for all users, enable conda with

    $ sudo ln -s /Users/matthewspeck/anaconda3/etc/profile.d/conda.sh /etc/profile.d/conda.sh

The options above will permanently enable the 'conda' command, but they do NOT
put conda's base (root) environment on PATH.  To do so, run

    $ conda activate

in your terminal, or to put the base environment on PATH permanently, run

    $ echo "conda activate" >> ~/.bash_profile

Previous to conda 4.4, the recommended way to activate conda was to modify PATH in
your ~/.bash_profile file.  You should manually remove the line that looks like

    export PATH="/Users/matthewspeck/anaconda3/bin:$PATH"

^^^ The above line should NO LONGER be in your ~/.bash_profile file! ^^^

解决方法：
每次在conda activate 之前在终端输入：

source ~/anaconda3/etc/profile.d/conda.sh

然后就可以conda activate了