Why can't I change my python version

Question

[LeeLee]

I am using some bioinformatics software that requires a python2 environment. I use conda to create a new environment and specify the python version as 2.7.18, but when I type 'python' I find that the python version is 3.9.5. I use the 'which python'code, and ls -l the link, and get return

> lrwxrwxrwx 1 leelee leelee 9 9月  22 20:06 /home/leelee/miniconda3/envs/clear2/bin/python -> python2.7

I type 'python2.7' and got the version I wanted. But it is still 3.9.5 when type 'python'. I am very confused about this, how can I solve this problem.

[ATpoint]

Did you activate the enviromnent?

[LeeLee]

Yes I activated

[Joe]

What is the output of which -a python with and without the environment activated?

[LeeLee]

When without activated return /home/leelee/miniconda3/bin/python,when activate return

/home/leelee/miniconda3/envs/clear/bin/python
/home/leelee/miniconda3/bin/python

[Joe]

Looks like something is wrong with your environments then, as the binary in use first when your environment is activated is .../envs/clear/bin/python, but the path you mentioned in the first post is .../envs/clear2/bin/python

There is a 2 in there which is presumably 2 different environments. Check if /home/leelee/miniconda3/envs/clear/bin/python is a link to a different binary.

I suspect the python you think you're calling (and is 2.7) isn't the one you actually are calling.

[LeeLee]

In fact, clear2 is an environment for me to test. Both clear and clear2 environments should be python2.7. But after relinking the python of the clear environment, I suddenly got python2.7, maybe I really confused it, thank you very much for your reply