为什么我在Python中使用matplotlib时收到此错误“ImportError：没有名为pyplot的模块”

Question

我下载了matplotlib wheel文件并使用pip安装它并成功安装。但matplotlib不包含pyplot。我该怎么办？

     UNIT                         LOAD   ACTIVE SUB    DESCRIPTION
● systemd-modules-load.service loaded failed failed Load Kernel Modules

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

1 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
lucas@debian8-1:~$ 
ucas@debian8-1:~$ systemctl --failed
  UNIT                         LOAD   ACTIVE SUB    DESCRIPTION
● systemd-modules-load.service loaded failed failed Load Kernel Modules

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

1 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
lucas@debian8-1:~$ systemdctl status systemd-modules-load.service
bash: systemdctl: command not found
lucas@debian8-1:~$ systemctl status systemd-modules-load.service
● systemd-modules-load.service - Load Kernel Modules
   Loaded: loaded (/lib/systemd/system/systemd-modules-load.service; static)
   Active: failed (Result: exit-code) since Tue 2015-06-23 12:53:00 CEST; 11min ago
     Docs: man:systemd-modules-load.service(8)
           man:modules-load.d(5)
  Process: 409 ExecStart=/lib/systemd/systemd-modules-load (code=exited, status=1/FAILURE)
 Main PID: 409 (code=exited, status=1/FAILURE)

  

错误：   将matplotlib.pyplot导入为plt   ImportError：没有名为pyplot的模块