import os
#當前存在的環境變量,可以在ipython中直接輸入下面這句查看keys
In [3]: os.environ.keys()
Out[3]:['LC_NUMERIC','LESSOPEN','SSH_CLIENT','LOGNAME','USER','HOME','LC_PAPER','PATH','LD_LIBRARY_PATH','SSH_CONNECTION','LANG','TERM','SHELL','LIBRARY_PATH','LC_MONETARY','LIBVIRT_DEFAULT_URI','XDG_RUNTIME_DIR','LC_ADDRESS','PYTHONPATH','SHLVL','CONDA_SHLVL','XDG_DATA_DIRS','XDG_SESSION_ID','_','LC_IDENTIFICATION','COCOAPI','LESSCLOSE','SSH_TTY','LC_TELEPHONE','LC_MEASUREMENT','PWD','LC_NAME','MAIL','LC_TIME','LS_COLORS']