Error in python3 PIP install Dlib:

Dlib has been installed before. It takes a long time. When you re install it, you forget some necessary conditions. This time, please make a note.

The error information is as follows:

Collecting dlib
  Downloading https://files.pythonhosted.org/packages/05/57/e8a8caa3c89a27f80bc78da39c423e2553f482a3705adc619176a3a24b36/dlib-19.17.0.tar.gz (3.4MB)
     |████████████████████████████████| 3.4MB 14kB/s
Building wheels for collected packages: dlib
  Building wheel for dlib (setup.py) ... error
  ERROR: Complete output from command 'f:\python36\python.exe' -u -c 'import setuptools, tokenize;__file__='"'"'C:\\Users\\fu\\AppData\\Local\\Temp\\pip-install-t50q34ym\\dlib\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d 'C:\Users\fu\AppData\Local\Temp\pip-wheel-g2i4oztb' --python-tag cp36:
  ERROR: running bdist_wheel
  running build
  running build_py
  package init file 'dlib\__init__.py' not found (or not a regular file)
  running build_ext
  Traceback (most recent call last):
    File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 120, in get_cmake_version
      out = subprocess.check_output(['cmake', '--version'])
    File "f:\python36\lib\subprocess.py", line 356, in check_output
      **kwargs).stdout
    File "f:\python36\lib\subprocess.py", line 423, in run
      with Popen(*popenargs, **kwargs) as process:
    File "f:\python36\lib\subprocess.py", line 729, in __init__
      restore_signals, start_new_session)
    File "f:\python36\lib\subprocess.py", line 1017, in _execute_child
      startupinfo)
  FileNotFoundError: [WinError 2] The system cannot find the specified file.

  During handling of the above exception, another exception occurred:

  Traceback (most recent call last):
    File "<string>", line 1, in <module>
    File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 261, in <module>
      'Topic :: Software Development',
    File "f:\python36\lib\site-packages\setuptools\__init__.py", line 143, in setup
      return distutils.core.setup(**attrs)
    File "f:\python36\lib\distutils\core.py", line 148, in setup
      dist.run_commands()
    File "f:\python36\lib\distutils\dist.py", line 955, in run_commands
      self.run_command(cmd)
    File "f:\python36\lib\distutils\dist.py", line 974, in run_command
      cmd_obj.run()
    File "f:\python36\lib\site-packages\wheel\bdist_wheel.py", line 192, in run
      self.run_command('build')
    File "f:\python36\lib\distutils\cmd.py", line 313, in run_command
      self.distribution.run_command(command)
    File "f:\python36\lib\distutils\dist.py", line 974, in run_command
      cmd_obj.run()
    File "f:\python36\lib\distutils\command\build.py", line 135, in run
      self.run_command(cmd_name)
    File "f:\python36\lib\distutils\cmd.py", line 313, in run_command
      self.distribution.run_command(command)
    File "f:\python36\lib\distutils\dist.py", line 974, in run_command
      cmd_obj.run()
    File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 129, in run
      cmake_version = self.get_cmake_version()
    File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 125, in get_cmake_version
      "\n*******************************************************************\n")
  RuntimeError:
  *******************************************************************
   CMake must be installed to build the following extensions: dlib
  *******************************************************************

  ----------------------------------------
  ERROR: Failed building wheel for dlib
  Running setup.py clean for dlib
Failed to build dlib
Installing collected packages: dlib
  Running setup.py install for dlib ... error
    ERROR: Complete output from command 'f:\python36\python.exe' -u -c 'import setuptools, tokenize;__file__='"'"'C:\\Users\\fu\\AppData\\Local\\Temp\\pip-install-t50q34ym\\dlib\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record 'C:\Users\fu\AppData\Local\Temp\pip-record-4kwg7hfv\install-record.txt' --single-version-externally-managed --compile:
    ERROR: running install
    running build
    running build_py
    package init file 'dlib\__init__.py' not found (or not a regular file)
    running build_ext
    Traceback (most recent call last):
      File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 120, in get_cmake_version
        out = subprocess.check_output(['cmake', '--version'])
      File "f:\python36\lib\subprocess.py", line 356, in check_output
        **kwargs).stdout
      File "f:\python36\lib\subprocess.py", line 423, in run
        with Popen(*popenargs, **kwargs) as process:
      File "f:\python36\lib\subprocess.py", line 729, in __init__
        restore_signals, start_new_session)
      File "f:\python36\lib\subprocess.py", line 1017, in _execute_child
        startupinfo)
    FileNotFoundError: [WinError 2] The system cannot find the specified file.

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 261, in <module>
        'Topic :: Software Development',
      File "f:\python36\lib\site-packages\setuptools\__init__.py", line 143, in setup
        return distutils.core.setup(**attrs)
      File "f:\python36\lib\distutils\core.py", line 148, in setup
        dist.run_commands()
      File "f:\python36\lib\distutils\dist.py", line 955, in run_commands
        self.run_command(cmd)
      File "f:\python36\lib\distutils\dist.py", line 974, in run_command
        cmd_obj.run()
      File "f:\python36\lib\site-packages\setuptools\command\install.py", line 61, in run
        return orig.install.run(self)
      File "f:\python36\lib\distutils\command\install.py", line 545, in run
        self.run_command('build')
      File "f:\python36\lib\distutils\cmd.py", line 313, in run_command
        self.distribution.run_command(command)
      File "f:\python36\lib\distutils\dist.py", line 974, in run_command
        cmd_obj.run()
      File "f:\python36\lib\distutils\command\build.py", line 135, in run
        self.run_command(cmd_name)
      File "f:\python36\lib\distutils\cmd.py", line 313, in run_command
        self.distribution.run_command(command)
      File "f:\python36\lib\distutils\dist.py", line 974, in run_command
        cmd_obj.run()
      File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 129, in run
        cmake_version = self.get_cmake_version()
      File "C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\setup.py", line 125, in get_cmake_version
        "\n*******************************************************************\n")
    RuntimeError:
    *******************************************************************
     CMake must be installed to build the following extensions: dlib
    *******************************************************************

    ----------------------------------------
ERROR: Command "'f:\python36\python.exe' -u -c 'import setuptools, tokenize;__file__='"'"'C:\\Users\\fu\\AppData\\Local\\Temp\\pip-install-t50q34ym\\dlib\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record 'C:\Users\fu\AppData\Local\Temp\pip-record-4kwg7hfv\install-record.txt' --single-version-externally-managed --compile" failed with error code 1 in C:\Users\fu\AppData\Local\Temp\pip-install-t50q34ym\dlib\
WARNING: You are using pip version 19.1, however version 19.1.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

Cmake and boost need to be installed before Dlib is installed. Then Dlib can be installed correctly

pip install boost
pip install cmake
pip install dib

Test installation results:

C:\Users\fu>python
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import dlib
>>>