This is a known limitation of the MATLAB Interface for Python Interface for Python versions 3.x and MATLAB versions R2021b and earlier. If downgrading to Python 2.7 is not a viable option, then there is a workaround that can be used to avoid this limitation.
1) Create the following Python file (called SysGetSys.py here).
import sys
def setPrefix(val):
sys.prefix=val
sys.exec_prefix=sys.prefix
print(sys.prefix)
def getPrefix():
print(sys.prefix)
2) Execute the following commands in MATLAB
>> s = py.list; % this loads Python
>> env = pyenv;
>> py.SetGetSys.setPrefix(env.Home) %this sets the new sys.prefix
>> py.SetGetSys.getPrefix % confirm the sys.prefix is set
After that, sys.prefix should work as expected.
