VScode debug console can not evaluate expression for C++

[rapplovin]

Hi there, I am trying to evaluate some expression in the debug console in VS code but got this error on both mac os or linux. The expression is copied from running code in current cpp file under debugging. Any suggestion is appreciated. Thanks!

/se myjson["value"][1]
'str' object cannot be interpreted as an integer
/se myjson["value"][1].toString()
Syntax error: myjson["value"][1].toString()
^
/nat myjson["value"][1].toString()
error: Couldn't lookup symbols:
__ZNSt3__117basic_string_viewIcNS_11char_traitsIcEEEC1EPKc
/nat myjson["value"][1]
error: Couldn't lookup symbols:
__ZNSt3__117basic_string_viewIcNS_11char_traitsIcEEEC1EPKc