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Use of installed libraries

A Python script starts with:
from pathlib import Path
import sqlite3
which I read as an initialization of Libraries needed to run the rest of the script. However if the following error is returned in the terminal:
ImportError: No module named pathlib
I am uncertain how to interpret this. One assumption is that the pathlib library is uninstalled. However on the local system Python 2.7 and Python 3.4 are installed (I believe one was system pre-installed).
How can a library be asserted to exist? In case it is missing, how can it be installed?

You have to install it first
pip install pathlib
And with that your code should work.

Unable to fully package my Python script with all the modules and dependencies it needs for Linux

I have a Python 2.7 script that uses BeautifulSoup4 and requests modules.
The issue is, that I need to deploy this script on a machine to which we can not directly install any new modules/libaries via pip install or anything else.
We can copy this script and any files it needs to run to that machine, but we can not directly install any modules.
I have tried PyInstaller, PEX and Nuitka to create an executable file or a bundle (in any format, for example .zip) so that we can copy the entire file or bundle into the machine and run the python script from there, without the need to do pip install or installing the modules manually via Wheel file. All without success.
Environment details:
Target machine on which the script needs to run: RHEL-based Linux OS with Python 2.7.
My development machine: Windows 10 but I also have access to Fedora Linux machine both with Python 3 and Python 2.7.
The import section of my script looks like this:
from __future__ import with_statement
from __future__ import absolute_import
import requests
import re
from bs4 import BeautifulSoup
from io import open
Can someone, please, help me out here?
We have the script ready to be deployed, but we are not able to run it in our target machine because of the missing modules/libraries.
Thank you very much
EDIT:
Mentioning this since it may not be clear at first - we do not have the issue with a network connection or anything of this gender. We were prohibited to use pip install or a manual method of installing a module. Therefore, we can only bundle the modules directly with the script or something so that would not need to directly install the modules on the target machine itself.

Python Libraries - Making them work on PCs that arent mine

Apologies if this is a very stupid question but I am new to python and although I have done some googling I cannot think how to phrase my search query.
I am writing a python script that relies on some libraries (pandas, numpy and others). At some point in the future I will be passing this script onto my University so they can mark it etc. I am fairly confident that the lecturer will have python installed on their PC but I cannot be sure they will have the relevant libraries.
I have included a comments section at the top of the script outlining the install instructions for each library but is there a better way of doing this so I can be sure the script will work regardless of what libraries they have?
An example of my script header
############### - Instructions on how to import libraries - ###############
#using pip install openpyxl using the command - pip install openpyxl
#########################################################################
import openpyxl
import random
import datetime

Distributing code is a huge chapter where you can invest enormous amounts of time in order to get things right, according to the current best practices and what not. I think there is different degrees of rightness to solutions to your problem, with more rightness meaning more work. So you have to pick the degree you are comfortable with and are good to go.
The best route
Python supports packaging, and the safest way to distribute code is to package it. This allows you to specify requirements in a way that installing your code will automatically install all dependencies as well.
You can use existing cookiecutters, which are project-templates, to create the base you need to build packages:
pip install cookiecutter
cookiecutter https://github.com/audreyr/cookiecutter-pypackage
Running this, and answering the ensuing questions, will leave you with python code that can be packaged. You can add the packages you need to the setup.py file:
requirements = ['openpyxl']
Then you add your script under the source directory and build the package with:
pip wheel .
Let's say you called your project my_script, you got yourself a fresh my_script-0.1.0-py2.py3-none-any.wheel file that you can send to your lecturer. When they install it with pip, openpyxl will be automatically installed in case it isn't already.
Unfortunately, if they should also be able to execute your code you are not done yet. You need to add a __main__.py file to the my_script folder before packaging it, in which you import and execute the parts of your code that are runnable:
my_script/my_script/__main__.py:
from . import runnable_script
if __name__ == '__main__':
runnable_script.run()
The installed package can then be run as a module with python -m my_script
The next best route
If you really only have a single file and want to communicate to your lecturer which requirements are needed to run the script, send them both your script and a file called requirements.txt, which contains the following lines:
openpyxl
.. and that's it. If there are other requirements, put them on separate lines. If the lecturer has spent any amount of time working with python, they should know that running pip install -r requirements.txt will install the requirements needed to run the code you have submitted.
The if-you-really-have-to route
If all your lecturer knows how to do is entering python and then the name of your script, use DudeCoders approach. But be aware that silently installing requirements without even interactive prompts to the user is a huge no-no in the software-engineering world. If you plan to work in programming you should start with good practices rather sooner than later.

You can firstly make sure that the respective library is installed or not by using try | except, like so:
try:
import numpy
except ImportError:
print('Numpy is not installed, install now to continue')
exit()
Now, if numpy is installed in his computer, then system will just import numpy and will move on, but if Numpy is not installed, then the system will exit python logging the information required, i.e., x is not installed.
And implement the exact same for each and every library you are using.
But if you want to directly install the library which is not installed, you can use this:
Note: Installing libraries silently is not a recommended way.
import os
try:
import numpy
except ImportError:
print('Numpy is not installed, installing now......')
resultCode = os.system('pip install numpy')
if resultCode == 0:
print('Numpy installed!')
import numpy
else:
print('Error occured while installing numpy')
exit()
Here, if numpy is already installed, then the system will simply move on after installing that, but if that is not installed, then the system will firstly install that and then will import that.

How to import a module with a dotted path?

I want to import the paramiko module located in /usr/local/lib/python2.7/dist-packages. So, I imported it this way:
from usr.local.lib.python2.7.dist-packages import paramiko
I have an error syntax related to python2.7 (It considers 7 as a package located in python2 package)
I have both Python3.1.3 and Python2.7 installed. I program with Python3.1.3 only, however.
How can I resolve this problem ?

How about ?
import sys
sys.path.append('/usr/local/lib/python2.7/dist-packages')
import paramiko
UPDATED
The best solution is installing paramiko on Python3 env. Take a look at #DanielRoseman's answer. Or virtualenv is worth consideration. Here is a good tutorial. http://simononsoftware.com/virtualenv-tutorial/

I don't know why you think you need to include the full path. That directory will already be included in the Python path. You just need to do import paramiko.
Edit after comment Well you can't randomly import things that are installed for a different version. There are several backwards incompatibilities, and anything that has any compiled extensions will just not work at all.
You need to download and install paramiko for your 3.1 installation, rather than trying to use the 2.7 version. python3 pip install paramiko, as an example.
(Also, you shouldn't really be using 3.1. If you're using the Python 3 series you should upgrade to 3.4.)

How to type into cmd using python 2.7

I have a program here that I would like to convert to 2.7. This code works well in Python 3.x, however, for my needs it must be 2.7. Could someone 'convert' this to python 2.7 for me? I have heard of a 3to2.py tool but I do know how to get/use it. Anyway, here is the code I have for 3.3.
def compiler(program):
import os, win32com.client, time
os.startfile("C:\\Windows\\System32\\cmd.exe")
time.sleep(2)
shell = win32com.client.Dispatch("WScript.Shell")
shell.AppActivate('C:\\Windows\\System32\\cmd.exe')
setup(program)
shell.SendKeys("py MyCompiling.py.setup("+program+") py2exe\n")
def setup(program):
from distutils.core import setup
import py2exe
setup(console=[program + ".py"])
compiler('test1')
EDIT: When I try to run I get
ImportError: No module named win32com.client
Do I have to install this module seperately? If so, could someone please post the link.

Yes, you must install the library separately. In fact, if you visit the SourceForge page, you will see that there is an entirely different binary available for 2.7. You will want pywin32-218.win32-py2.7.exe if you are using 32-bit Python or pywin32-218.win-amd64-py2.7.exe if you are using 64-bit Python.
You can install it via the GUI interface (which comes up when you try to execute the file), or you can call easy_install on it (if you have setuptools or distribute installed) at the command line:
C:\> C:\Python27\Scripts\easy_install pywin32-218.win32-py2.7.exe
Using easy_install is the only way if you want to install the library in a virtual environment created with virutalenv.