Since I am using Spider, I should use "conda install". But some packages can not be installed in "conda install" while they easily can be installed in "pip install". For example, I installed Keras in "pip install" but in Spider, Keras can not be imported (Keras is not known). Then, I again installed Keras in conda install form.
On the other hand, some packages which were installed in "conda install" could be used and imported in python IDE or Spyder and vice versa.